It doesn't suck "getting old" -- and you only find out about stamina by trying to do things ...
(We are fortunate that most of what is "new" is more like "particular 'news'" rather than actually "new". From the standpoint of actual categorical change, things have been very slow the last 30 years or so.)
But, it's also worth looking at places where there's been enough change of one kind or another to constitute "qualitative". This has certainly happened in many areas of engineering and in science. How about in computering?
Can you explain more about what in UIs you think has gone downhill? I've seen you refer to this idea in quite a few of your comments and it would be great to get insight on what aspects you think need improving/exterminating/rethinking.
But let's see -- how about UIs giving up on UNDO, not allowing or not showing multiple tasks, not having good ways to teach how to us the UI or the apps, ...
(We are fortunate that most of what is "new" is more like "particular 'news'" rather than actually "new". From the standpoint of actual categorical change, things have been very slow the last 30 years or so.)