As two new casinos are shoe-horned into New England’s increasingly crowded gambling market, ever higher levels of revenue are hard to come by.

“You’re looking at a pie that’s been cut up way too much. Now you’re looking at adding more,” said Alan R. Woinski, president of Gaming USA Corp., which follows the industry. “You cannot put more casinos into this market. There’s no ifs, ands or buts.”

In just 10 months, between August 2018 and June, the region’s casino market added MGM Springfield, a $960 million downtown casino and entertainment complex; and Wynn Resorts’ Encore Boston Harbor, a $2.6 billion resort in Everett, Mass. Connecticut may add casinos in East Windsor and Bridgeport, in addition to Mohegan Sun and Foxwoods Resort casinos.

MGM Springfield generated revenue in its first year that was just 61 percent of what it projected when the casino was first proposed back in 2010. Part of the reason is the company underestimated gamblers’ loyalty to Mohegan Sun and Foxwoods, President Mike Mathis said Monday.

“Convenience and loyalty (are) what’s most important,” said Peggy Holloway, a senior vice president at Moody’s Investors Service. “People will travel to places that are most convenient. MGM Springfield is ramping up more slowly because it’s harder to get customers away from the Connecticut casinos.”

Revenue also took a hit at the two Connecticut casinos that have operated for nearly 30 years, most of that time with virtually no competition. Mohegan Sun generated $567.5 million in slot revenue for the state’s budget year that ended June 30, off 6 percent from the previous year. Foxwoods’ slot revenue of $443.2 million was down 7 percent.

A fall-off in revenue at all three casinos suggests MGM Springfield and the two Connecticut casinos are taking business from each other. Still, revenue at the tribal casinos was falling long before MGM Springfield opened as consumers cut entertainment spending during the Great Recession and slow recovery that followed.

“When revenue is flattening, that’s an indication of market saturation,” said Joseph Weinert, executive vice president of Spectrum Gaming Group, an industry research company. “As markets grow, each new entrant is going to cannibalize from other properties.”

Mathis brushed off talk of casino saturation.

“I think we’ve proven MGM can grow the market. Encore can grow the market,” he said Monday.

Financial hits aren’t felt only at the casinos in western Massachusetts and Connecticut. George Papanier, chief executive officer of Twin River Worldwide Holdings Inc., the parent company of Twin River Casino in Lincoln, R.I., told industry analysts on a recent conference call that Encore is “clearly experiencing a prolonged trial period” affecting its Rhode Island neighbor. The Wynn casino opened June 23.

The “new competition had a greater than expected negative impact” on table games at the Lincoln hotel and casino in July, Twin River said as it released its second-quarter financial results. It revised its expectations for operating income to be lower by about 10 percent from previous guidance, but Stifel analysts Brad J. Boyer and Steven M. Wieczynski said in a note to clients they believe Twin River’s estimate is conservative. They issued an optimistic “buy” recommendation for Twin River stock.

Table game revenue at Twin River fell in July by about $3.9 million, or 34 percent, to $7.6 million over July 2018. Net income from slots decreased about $6.4 million, or 17 percent, to $32.2 million in the same period, Twin River reported.

That’s “well above” the range of between 10 percent and 15 percent that management previously set as guidance, Boyer and Wieczynski said.

Encore Boston Harbor pulled in $65.4 million in revenue in its first five weeks, through the end of July. A casino typically ramps up to its potential in two or three years, and growth then tends to slow, Weinert said.

Bloomberg Intelligence analysts Brian Egger and Caitlin Noselli said Wynn’s initial table game results were robust and put the resort “firmly on its targeted three-year path to $1 billion in revenue.”

“Encore clipped table results at Rhode Island rival Twin River by reaching Wynn Las Vegas’ win-per-table level, twice our assumption,” they wrote Aug. 19. “However, its slot performance lags behind New England peers.”

Woinski said the consequences of more gambling, such as stagnant or declining revenue, are not surprising. Despite the persistent specter of casino saturation, “they keep building,” he said.

“The logic in the gambling business is if they don’t do it, someone else will,” he said.

Holloway said the industry has reached saturation, but casinos will “keep building if they think they’ll have a decent return,” which generally is a function of what states charge in taxes or fees.

Two factors are at work in the casino boom in the Northeast. The Las Vegas-based MGM is establishing a presence on the East Coast, with casinos in Atlantic City, Maryland, Springfield and Yonkers, N.Y.

“They’re quietly building an empire in the Northeast,“ Woinski said. “If they have one under-performing casino and the others do well, they’re ahead of the game.”

James Murren, MGM’s chief executive officer, said as much on a conference call last month with industry analysts as he explained the revenue miss at Springfield. It posted slot machine and table game revenue of $253 million between its opening in August 2018 and July 31, short of the $412 million it expected.

“So if we are behind in someplace, like we’re behind in Springfield, we’re ahead in many other places, and that is the value of being a diversified company,” he said.

A second driver in the construction of more casinos is that state officials are competing aggressively with out-of-state competition to keep taxed revenue at home. Lawmakers in several states “are very concerned about keeping gambling dollars in state,” Weinert said.

“Their answer: Expand their gambling casinos,” he said. “They do not want to see gambling dollars cross state lines and taxable revenue leaving.”

Legislative allies of the Mohegan Sun and Foxwoods Resort casinos have introduced legislation in the General Assembly to establish a gambling site in Bridgeport to be run by the tribes. MGM, which is barred from the deal, is suing.

Andrew Doba, a spokesman for a joint Mohegan-Mashantucket Pequot venture planned for East Windsor, said he’s surprised Mathis would talk about Connecticut competition “with a straight face.”

“They literally filed suit against (East Windsor) just a few days ago,” he said. “That’s a pretty aggressive tactic to take for a facility you don’t care about.”

Woinski questioned the strategy of the Mohegan Sun-Foxwoods joint venture for a casino in East Windsor to detour customers bound for MGM Springfield.

“Why put one in East Windsor? Common sense says that the market cannot support another casino,” he said. “The real threat is Encore, not MGM. The market is not deep enough for MGM where it is.”

State Sen. Cathy Osten, whose district is home to the tribal casinos, said analysts have told her the “exact opposite,” that an East Windsor site would generate more revenue than a Bridgeport casino.

In addition, she said, Encore’s hotel rooms are not cost-competitive, reducing the potential threat to Connecticut’s casinos.

Wynn Resorts Ltd., MGM Resorts International, the Mohegan Sun and Foxwoods are “major operators operating major facilities,” Weinert said. And Twin River, the flagship of its corporate parent, “is no slouch.”

“This is a heavyweight battle taking place in new England,” he said.