Yes, a mixture of reasons.
Cutbacks - less postmen, more for each to deliver.
change in delivery format - no longer 2, now just one where everything that is in has to go out.
More mail to deliver - especially junk.
and the last, some time ago they changed all the start times so we have to start an hour later. At my office, I amlucky if I get out by 9.30, and the last letter will still be about 1.00.
Some get there post early round here because spme go out and do a bit - probably the same all over.