I think that the issue with that is that a lot of facilities might not be able to handle the volume of people coming in to pickup thier mail. My PO is one of them. Parking sucks, there are only a couple hundred PO boxes and there's probably 5,000 people served by my PO so there wouldn't be the PO boxes for everyone, the building is small so having more than a few people inside at a time things get cramped...the idea of going to the PO doesn't bother me too much. A little inconvenient but if it'll save jobs and possible the USPS as a whole, I'd suck it up and go pick up my mail.
Our branch is located on a horrible stretch of road. If everybody in rural locations had to drive, even every other day, it would be madness and the larger branches would have to spend unthinkable sums to expand their P.O. box availability. The cost would be something to reckon with.