I hear ya.
The past few years have not been kind to me, and the fact that I've not exactly been kind to myself has only expedited the process. The sad thing is that I'm not nearly as old as I feel. But I continue to play, knowing that in all likelihood that I'll never again know what it feels like to shoot 68 from the tips, or go into the opening round of a club championship not only thinking I can compete, but truly believing that I'm gonna win.
A majority of the guys I play with on a regular basis are older than me, a couple of them considerably older. I'm only 47 years old, still a young pup really. My best friend is 65, plays the member tees still, even though he could move up a set if he wanted to. Although it's just 6500 yards, it is a long 6500 yards, because our fairways are usually soft. He still hits it about 240, and he shot 75 last Saturday. He's still got some game, says he's hitting it just as far now as he did when he was younger. Then another guy I play with regularly, just turned 70 last summer - he has crazy length not only for a guy his age - but a guy as short as he is, and not exactly athletic to boot. When he's swinging well - he still moves it out there about 270 on occasion. He is blessed with tremendous flexibility. But like lots of guys his age - the cups just seem to be about 3 inches smaller than they used to.
So I totally concur with your thought process. These older guys are just as competitive now as they were 30 years ago, maybe even more so. Sure - technology has made a huge impact on them getting better with age, but still It gives me hope that maybe there's enough time for me to get my conditioning back to a level where I too can sustain that type of quality playing at their age.