Since the city’s real estate sales market peaked around 2016, observers have focused on the shrinking price tags of ultraluxury three- and four-bedroom apartments, thousands of which remain vacant and unsold. The causes are many: investor speculation, oversupply, shrinking tax breaks, rising transfer taxes, economic uncertainty and downright hubris.

The current declining prices in smaller apartments, though, represents a significant shift and the return of more reasonable pricing. Two-bedrooms made up 31.5 percent of Manhattan’s for-sale inventory last quarter, the most of any category, according to the Elliman report, and has long been the bread-and-butter of both developers and agents. The two-bedroom market accounted for half of all sales at one point in the 1990s, but in more recent years, the ultraluxury condo boom in Manhattan has prompted a move to bigger and more lavish apartments — many of which were targeted to investors and second-home buyers, said Jonathan Miller, the president of Miller Samuel Real Estate Appraisers & Consultants and author of the report.

Still, upgrading from a smaller apartment to a two-bedroom remains cost prohibitive for many New Yorkers, Mr. Miller said. Last quarter, it cost a median $685,000 more to move up from a one-bedroom to a two-bedroom in Manhattan.

Those forces — too expensive for many move-up buyers, too small for the affluent jet set — have squeezed the two-bedroom market into an awkward position for many sellers, said Tyler Whitman, an agent with Triplemint and cast member on the reality series “Million Dollar Listing.”