As others have said, it is likely the companies themselves owning giant, expensive, heavily-branded campuses that weren't designed with modularity and reselling

As others have said, it is likely the companies themselves owning giant, expensive, heavily-branded campuses that weren't designed with modularity and reselling in mind. 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.