The business rationale for Business Class travel will remain: you can't expect people to travel overnight and be productive the following day if they haven't had any sleep. So, for lowly paid people, and if hotels are cheap, you let them lose a day. For highly paid people, you buy them Business Class.
I would suggest that, if there's a significant change, it will be to economy class over the next couple of years (at least until this episode becomes a distant memory). Will enough people be prepared to be squashed into tiny seats? Or will enough people be prepared to pay extra for some space? Only time will tell, but I have no doubt that innovative airlines will be playing around with alternatives, trying to find a new sweet spot.