“Back in the day, the great incentive to owning was that the product was better than a rental,” said Stuart Moss, an associate broker at the Corcoran Group. “But what happened was that many condos were built, and as a renter in those buildings you could get the high-end finishes. You no longer had to buy to get that quality and that more sophisticated design.”

In response, developers of rental properties have raised their games. With buildings like 456 Washington in TriBeCa, where rents are $9,500 to $45,000 a month, and the Easton on Third Avenue and 92nd Street, “we’re providing a long-term rental alternative for people who can truly afford to live anywhere in the city,” said Bryan Cho, an executive vice president of the Related Companies, who listed features in these buildings like custom millwork, marble bathrooms, elegant finishes and high-end appliances.

“We had a broker tell us, ‘My clients have $9 million to spend on a co-op or condo, and they’re getting frustrated because they can’t find the home of their dreams,” Mr. Cho said. “‘They’re making compromises and feel embittered about it.’ And then the client says: ‘Why don’t I keep my liquidity working for me? Why don’t I buy a country place somewhere and why don’t I just rent the best?’”

He also talked about a few couples who bought prewar apartments on Fifth and Park Avenues and who, during the subsequent renovations, rented at the Easton, where, depending on the size of the unit, they paid from about $5,000 to $22,000 a month. “They love it so much that now they want to sell the co-op they bought and just stay at the Easton,” he said.

Uncertainty about the direction of their career or personal lives also keeps some people renting. Amanda Bradshaw is both admirably frugal and, after a succession of jobs, comfortable in her position as the director of human resources operations for an investment bank. She is at a point where she could buy — but, first off, there is that frugality. Second, she lives in a one-bedroom on the second floor of a brownstone in Midtown East, “and it’s very me,” she said. “It has great moldings and hardwood floors and a big kitchen, and it’s near SoulCycle.”