Peal ringing decline "I'd love to hear what the benefits are, other than bragging rights and masochism?"
When I asked a similar question in about 2013, I was told very simply, that it would take my ringing to the next level. I rang my first 3 peals in 2015 and they definitely helped me to progress. Talk to the sort of ringer who can ring a decent repertoire without any mistakes, and you are probably talking to a peal ringer. Building the sort of mental and physical fitness required to ring a peal (or many peals) is very good discipline for a ringer, just as training for marathons is good for amateur runners.
So yes, the decline in Peal ringing will probably cause a significant decline in the number of ringers who are very good. It takes 10,000 hours to make a good musician and I would suggest it is no different with ringing. Getting 3 hours in one go is a pretty good way of inching towards those elusive higher levels.
Is it the same as ringing 4 quarters in one day? No, it's different. A marathon is different from 4 sprints.
So John, if you are offered a rope in a peal and you are fit enough to do it, I would encourage you to say yes!