What better way to spend piles of cash you have no idea what to do with than extort local governments for billions in tax breaks and park that money in a some commercial real estate you can depreciate? I'm not judging these companies for doing this per se (Amazon, Apple, and Google have all recently done this as far as I can tell - haven't noticed anything from Microsoft), but I do consider it a bit ominous that they've all picked expensive places that certainly seem like good picks.
It really does seem like these companies have no idea what to do with their money. Buying up land and taking the next 3-5 years to build billion dollar campuses seems so boring to me.