Getting older comes with challenges. For the architect and designer Matthias Hollwich, one of the more taxing ones is something often taken for granted: moving.

His point — that leaving behind friends, social connections and the purpose of a particular job can be physically and psychologically debilitating for older adults — underscores how developers, architects and city leaders are reimagining the retirement home.

“I want to give people the power to change their living conditions without moving away,” he said.

Mr. Hollwich, a co-author of “New Aging,” is developing a new senior living concept. Aiming to retrofit an office building in Manhattan left bare by remote work, the concept, called FLX Live, will feature communal dining, spa and co-working spaces and shared suites in which older adults, sleeping in private bedrooms with kitchenettes, will share living rooms with younger renters, resulting in lower rent for both parties. Operators will deliberately recruit an age-diverse community.

Driven by an aging population, a more active vision of retirement, and a shortage of senior housing options and support services, developers are increasingly embracing this urban village model of housing, which offers a sharp contrast to the typical isolated suburban retirement communities.

These projects are becoming more viable as city and business leaders realize that seniors can help support local shops like cafes, bookstores and salons.

“The stigma around older adults is going away,” said Tama Duffy Day, an architect and principal at the architecture firm Gensler. “Hospitality and residential developments understand that older adults are a huge market.”

Affordable senior rentals in urban areas would have been a dicier real estate proposition decades ago, when homeownership rates were higher and more mortgage-free older Americans hoped to age in place, decreasing the pool of potential renters. Seniors still predominantly own their homes, but demographics are shifting. An increasing number of adults in their 30s and 40s never plan to own a home, per recent research from Apartment List and the Federal Reserve Bank of New York.

A more diverse older population, increasingly without close family connections and often hard hit during market downturns like the 2008 recession, means the number of affordable units needed for future seniors is “daunting,” said Jennifer Molinsky of Harvard’s Joint Center on Housing Studies. The United States will have 16 million middle-income seniors by 2033, according to research by N.O.R.C. at the University of Chicago, a social research organization.

This new approach to senior housing, especially for those without serious medical issues, focuses on local resources, a model that not only serves both younger and older renters, but also can offer cheaper rent, because the connection to community organizations and the shared amenities of nearby parks and public programming can reduce the cost of providing such services in-house.

Kallimos Communities, a development concept created by Bill Thomas, a leader in progressive senior housing, features multigenerational neighborhoods of 50 to 60 smaller homes, with common spaces and programming staff who will plan group meals and social events. Developments are in the works in Victoria, Texas, and Loveland, Colo., where Kallimos is teaming up with a local housing authority and plans to break ground in 2024.

The initial response has included significant interest from older couples “seeking to be part of a community,” said Megan Marama, the chief operating officer of Kallimos.

In Britain, a model called RightSizer is being used to renovate and refurbish empty Main Street businesses decimated by online shopping and transform them into a mix of senior housing sites and community-focused health and education centers. The plan will reinvigorate local culture and business, said Rory O’Hagan, a director at Assael Architecture, which devised the idea. He added that he was working with developers to get approval this fall for the first site in South London.

Many developers of urban senior living rentals have tapped into the value of intergenerational living, integrating senior apartments with younger renters to stave off loneliness and share costs.

Bridge Meadows has successfully developed four such facilities in Oregon where seniors, foster children and their foster parents live in the same building. Part of impetus for the project was seeing elders who felt that “they were being put out to pasture” and wanted to feel vital to a community, said Derenda Schubert, the executive director of Bridge Meadows. Her design team is looking at ways to build on a larger scale.

Some developers, like McNair Living and Tabitha, have focused on building senior living facilities near college campuses. Next fall, Tabitha will open a 128-apartment intergenerational facility in Nebraska with the Bryan College of Health Sciences, offering 25 college students a chance to live closer to campus and supplement their classroom learning with real-life experience interacting with and living alongside elders.

“The moderate income price point for senior living is poorly served,” said Joyce Ebmeier, Tabitha’s chief of staff. “When you’re competing with high-end product, with lots of grand entrances and grand pianos and plush amenities, you need to think about creating a product that will serve people.”

The “awakening” around housing that has a more communal orientation parallels the way cities, in the pandemic era, are rethinking how to reinvigorate downtowns with more residential conversions; strict categories and rules are being revisited, said Ms. Day of Gensler.

“Cities are becoming more aware of the fact that we need to keep people in these cities and in an urban setting for it to remain active,” she said.