These days I get my stamps at my supermarket customer service desk when I'm running low.
The only reason I generally need to go to a post office is to mail a package, and I think a combined FedEx/UPS/USPS desk at a local Staples is more cost effective than separate store fronts.
They’re consolidating post offices in my area; at this point it seems they know they are a thing of the past and just want to see the last existing employee through to their retirement.
If we had a “do not send junk mail” list the way we have a “do not call” list then these conversations would have taken place decades ago; I wish the environmentalists would get all over the trees dying for the 90% of my mail that is unsolicited junk (and ends up shredded without opening).