They are doing so, in part, by footing the bill.

While some of the party’s elite donors have shunned Mr. Trump’s coronation this week, they are still paying for it. Roughly 500 wealthy Republicans poured close to $16 million into the Republican National Committee’s convention account leading up to this week, according to disclosures made to the Federal Election Commission through last Friday. The biggest donors, giving more than $100,000 each, are also a veritable roll call of the stop-Trump movement, among them the billionaire investor Paul E. Singer and Marlene Ricketts, who bankrolled early efforts to deny Mr. Trump the nomination.

Mr. Singer did not attend, though his political advisers made the rounds in Cleveland, as did representatives for other megadonors who remain opposed to Mr. Trump. And there were growing signs that at least some of the party’s biggest givers were warming to him: Co-hosts of Monday’s super PAC reception at the Ritz-Carlton included Harold Hamm, a billionaire oil tycoon and former energy adviser to Mitt Romney, and Stanley Hubbard, a Minnesota television station owner and prominent donor.

Among the guests was Foster Friess, the Wyoming-based mutual fund investor and super PAC donor, who expressed optimism at his party’s prospects. “I think it could be a landslide,” Mr. Friess said in an interview. “Donald Trump has the ability to reach all the plumbers and carpenters and factory workers who usually vote Democratic.”

Mr. Trump, of course, remains unpopular among many Republican donors, and it is unclear how many will ultimately open their wallets to help fund his campaign. Some events were more sparsely attended than they would have been four years ago, Republicans said. It was a little easier to get tickets to concerts in Cleveland, a little easier to get bumped up to the premium hotel rooms.

And there is no question that Mr. Trump’s blasts against unfettered trade and Wall Street banks have unsettled powerful business interests — and are now, to some extent, reflected in the party’s own DNA. In recent days, Trump activists have helped install new planks in the party platform calling for tougher trade negotiations and for reinstating the Glass-Steagall Act, the Depression-era law that walled commercial banking off from investment banking.

Yet those same power brokers won a more consequential victory even before the convention started, when Mr. Trump’s team helped them quash a rule proposed by some conservative delegates that would have banned lobbyists from serving as Republican National Committee members. The proposal by supporters of Senator Ted Cruz of Texas pitted Tea Party conservatives against the party’s business wing; the conservative delegates were soundly defeated.