Maybe there's some 19D "soft layoff" motivation, but I suspect a large part is just about control and appearance. You spent all that money on offices so workers better be there. And what's the point of having your own nice big office if you can't look out on the peons toiling for you? And more fundamentally, some people just have this deep belief that work = something you do in an office and can't compute working at home as "real" work, no matter what the results show.