I'll also observe that even though transit ridership is still lower than pre-pandemic levels, VMT is back to normal and increasing. People are not going to work as often, but they are going somewhere.
Why are they choosing to drive instead of ride transit? Perhaps it's because their destinations are longer range, and/or less predictible, and/or less radial than the traditional 5day/wk commute to and from the office. Or, perhaps it's because service is worse now. Probably, it's both.
This first hypothesis is something I have not seen discussed, but for me at least a big one I have experienced. Working from home also has created a massive amount of additional flexibility. For example, I might have a zoom meeting at 9 and another a 1, but that means that I might choose to go shopping, buy lunch, or run other errands in the day. I wonder if examining how and when people are running errands would explain a lot of the increase back to normal of VMT. First, a lot of people I know who do, or did, use public transportation for work commutes would rarely use it to run errands. The benefit to choosing to take a much longer time to get to a destination is in large part related to how long you're going to be there. If it takes me twice as long on the T to get work for 8 hours, that problem is outweighed by the hassle of traffic, expense of parking, etc. But if I want to go pick out new furniture or go to an appointment, things that take only an hour, it's much harder sell if that trip takes 15 min by car but 45min by the T. Now, this matters even more if you're trying to cram in a trip to the dentist when you have 2 hours between zoom meetings, for example: I think people are often trying to seize pockets of time they have to go get stuff done while working from home, and when you are already at home, it tends to be both physically easier and also psychologically easier to just hop into the car and go get something done, versus the barriers to doing this if you were at the office in downtown (where even if you might have driven, you have to walk to the car, etc—it's harder). Add in the fact that people traditionally used the weekends to get many errands done. You have a series of errands, and you do them all on Saturday, yes with a car, but it's still only one trip. The allure to get some of these things done in the middle of the day might mean that people are actually making more individual trips in the weekday, rather than clustering trips one a single day. It has certainly seemed to me that there is more auto traffic within Boston and Cambridge during the weekday than there used to be.
In any case, this is going to be a real challenge for which there really aren't easy solutions. We definitely need more investment in public transit and good transit does induce demand, but no amount of investment will change the fact that auto-centric settlement patterns are deeply woven into our way of life. In either truly dense urban environments like medieval European cities, or in very large and reasonably dense cities like in Manhattan, perhaps you can find almost everything you need by walking and transit fairly easily. But in most of the US, it's just not like that. Even if residential density was 5 times what it is, that doesnt change the fact that our shops and small business are flung all across highways (and often, for any niche service interest or shop, it's less and less likely to find that in city given rents, so more likely you're gonna be driving out to 495 or at least 128 to find it). We've unfortunately created a built environment that just doesn't work well with anything other than auto travel, but cant really sustain any more cars on the road, so here we are, at an impasse. It's hard to really see how this changes without any truly society-level restructuring, which has about a zero percent chance of happening.