The editors over at Bloomberg must be getting paid by article, for each article that espouses the religion of working in an office. I think the propaganda has failed catastrophically. No one's buying it.
These cities will be fine. Yes, they will change, but not expire. It will likely be painful for the building owners, but I don't think urban cores returning to everything Jane Jacobs held dear needs to be lamented. A shift back from single-use zoning and to the return of buildings built to human scale, street life, charm... all of it, wouldn't nearly be the loss that the propaganda pushers think it'll be.
It's not like the money just disappears from the economy. It's now being spread around to a greater variety of cities/towns, leveling the playing field and spawning a return to localism. That anyone would think this process is a bad thing seems extremely shortsighted.