To be fair, we always try to make a pa, but my SOP's dictate that we can only make them in the cruise. On a longish sector this is no problem, but on a 35min flight if you get distracted in the cruise (which can be as short as 5 minutes in total) with other flight duties as pilot flying, you can be descending before you have chance to make a pa. Also, ATC sometimes ask you to descend early, this means your planned pa no longer happens.
In short, nothing to do with eroding customer service, but the whole industry is concentrating on avoiding potentially hazardous level busts when going up and down. Making PA's takes 1 person out of the loop.
We always give everyone a 10 mins to landing though!