I think the one thing that gets lost in the work from home push is that it really takes good managers to make it work. You need a manager skilled at making sure that people are working at a good pace. Doing one-on-ones in person for a good people manager is a lot easier than over a video call where only a portion of you is visible, so a remote manager needs to be really good at remote one-on-ones. You need a manager that can fairly rate their reports so they push for promotions/raises/rewards based on their accomplishments. Without this, good performers get angry and leave. You also need a manager who can figure out if someone is not doing a good job and how to help them or move them out of the org. The manager also needs to have the skills to onboard new hires since mentorship is going to be a bit more difficult when done remotely since nearly no company has good documentation for new hires.
A decent manager might struggle with these skills when going fully remote. It could be easy for them to fall back on some rudimentary metrics of productivity because they have a hard time judging what people are doing. You will probably see managers who have "favorites" lean more heavily on a few people because they are a known quantity to the manager. You'll probably see new hires take a lot longer to get up to speed with merely competent managers.
I wonder if we actually have enough good managers to make work from home scale up.