I think many of them want to sell their buildings and cash out. The land is worth a lot more without old buildings and rent stabilized tenants on it. They want to build new modern buildings with all the amenities, multiple indoor and outdoor pools, heated lap pools for apartments with views, gyms, shops and fine dining, bistros, cafes, roof gardens, underground, gated parking for all your cars and staff, security at all entrances and regularly checking every single spot in the complex except in tenants apartments, freight elevators for big stuff like grand pianos, (otherwise impossible to get into apartments without using an outdoor crane) two or more story penthouse apartments with spectacular views, art, ornate lobbies, 24/7 security and CCTV doorbells, very thick concrete walls so no noise from neighbors, even ones with children, backup power systems, thick pile carpeting, extensive marble, all new stainless steel luxury brand appliances, Internet hotspots in the common areas. In house personal trainers, top rated multiple on site restaurants with world famous chefs/bars and meeting rooms, access control system to offer fine grained control over servants and residents, and family members ingress and egress, in some cases also marina facilities and boat slips, fuel available for your boats and at heliport. (See the big H printed on the roof -visible in Google Earth)
Depending on how much they pay, buyers expect amenities in varying degrees. many people live in a home and thats their choice, but many others live in apartments because they have access to all this stuff they only need occasional use of but which they like having.
That is the way many wealthy people live. These buildings ae everywhere now. Self contained little worlds. Owners/members are very busy and also security conscious and also they want to be able to come and go quickly, fly to the local airport quickly and jet away to wherever. Helicopter taxis serve some of these buildings on request. Its like a jitney bus, except with rotors. It saves hours in traffic or on the subway. They are not cheap though. Other helicopters (and direct busses) are relatively cheap but they offer service between some midtown locations and airports, not pickups at your roof heliport.
In some areas “helicopter parents” literally have their children brought to and from school by helicopter to avoid the security risk of driving them in a bulletproof car with their bodyguard.