I wonder how much of it is driven by the company leadership owning very expensive real estate that would lose a lot of value once tech workers are not forced to spend money into those rental or real estate markets.
However, making decisions based on this is a pretty classic sunk-cost fallacy. The cost of continuing to use the campus won't be any higher because it's half-empty.
So I don’t think this has to do with executives protecting home values. It might be about the business protecting the value of office buildings, though - if they own them, and don’t rent, anyway.
That probably makes those spaces harder to sell/rent. It's unlikely they'll find a single large buyer with the same needs. They'd probably have redesign the campuses a bit to better support multiple tenants.
I’m pro-remote work, but if all of tech does it, that seriously dents tech-style real estate.