I thought this was bound to happen due to the sabotage of the post office that is somewhat bipartisan but increased with Trump term 1. But yesterday my grandmother just got a birthday card she had sent to me two years ago returned as “undeliverable” despite the address being correct and the postage paid. And this also caused me to find out that this happened to several other relatives, though without the two year delay, despite the address and postage being definitely correct.
There has been a noticeable decline in the past three or so years, yes. I’ve had a number of packages entirely lost, including my new passport (!!!). The reason frequently cited is that same “undeliverable address” issue you posted about, despite yes the address being 100% correct.