I see two reasons to go back to the office: 1. You need a physical space to work from. 2. Your entire team is at the office as well and you can collaborate with them face to face. I imagine 1 is not a concern for most people who have adapted to the situation over the last two years. And 2 requires that most of your team is local and agrees to come in as well, which I can't see being too likely. For me personally goin…
Although I have no issues motivating myself to get work done on my own (of course I have off days when I struggle - in the office it actually seems easier to get away with that without feeling guilty), one thing I always found hard was work life balance. You see it's 5pm but you are knee deep fixing a bug, so you power on with it, and before you know it, it's 6:30pm. In an office when you see everyone else leave you know it's time for you to as well - the bug can wait, no big deal.
I think what doesn't help is that I've never had a dedicated office room at home, I've had a cramped office corner of my bedroom, but it's not quite the same. I'm guessing Google's employees in SF, NYC and London are also in a similar position, so I don't really see there being much push back.
If someone moved from NYC to some remote part of PA they can apply to work remotely, and if Google says no, there are plenty of other companies who will take them. At the same time, there will be plenty of people who want to live in NYC and work for Google. There may be a higher turnover this year, but long term I don't see it being an issue.