I'm not sure that viewing this as some kind of dry run for a future in which we all work from home is particularly fair, on multiple fronts. Firstly, this isn't a choice anyone has made, it's something which has been forced upon them. Working from home is (for some) great, but in its present state, many are restricted from leaving the house unless absolutely necessary, and so we're not so much "working from home" as "living from home". I think is a crucial difference, because people are currently denied any physical form of socializing, not merely during working hours. The speed at which this situation was forced upon us, also means that few of us have the separate room with perfect working conditions which a typical full-remote worker might.
From the perspectives of the companies it's also unfair to look at their hiring habits and speculate on their attitudes to working from home. Many companies are struggling to meet payroll, fighting with uncertainty, and desperately trying to form new communication structures in order to support the business. During such time, of course hiring is not going to be a priority.
Speculating on the outcome of this nightmare seems somewhat foolhardy, and extolling the virtues of working from home myopic given the many people who now find themselves struggling or out of work, ill, or forced to work in what are increasingly dangerous environments.