Anyone who was thinking of selling but doesn't urgently need to will delay until it's not so much of a buyer's market. But this means there will be a buildup in the number of people who have been waiting to sell. So prices will recover slowly because it will be necessary to chew through this backlog.
But, as in any downturn, there are people who are sitting on cash and looking for bargains. They will buy up some of what's for sale. (Downturns always create chaos, and there are people who are financially ruined and other people who multiply their wealth dramatically.)
According to [1], as of 2015, 77% of commercial real estate is owned by private equity and REITs. Those types of investments primarily generate returns via dividends that come from rent. So it seems like most investors can't let them sit empty?
[1] - https://www.thebalance.com/what-is-commercial-real-estate-33....
As a result, there's also a whole bunch of subleasing going on in commercial RE, hence, it may end up being a whole chain of random third-parties taking the loss for the owners of the buildings (e.g., companies that need to move out of their office after outgrowing it, etc). Surprisingly, this might make an even better argument for the come-back of WeWork -- their whole model from the start was to makeover the buildings abandoned by the tenants.
Likewise, it may not affect the sale price at all, because noone would want to tank their own REITs, even if the market itself is stale -- the owners have a vested interest in keeping the bubble afloat.
I would imagine companies like WeWork may actually come out ahead here; because if your own company doesn't provide you with a place to work away from home, you might still need an office somewhere.