I can see some of your point. Long ago I was a pretty good swimmer. Good enough to practice with a college team when I was still in high school. Qualified for nationals, had dreams, blah blah. Got hit by a diver in practice my sophomore year in college. Missed most of the season, tried to come back and sucked the big weenie. Gave it up.
I had the talent, I could put in the training, but I couldn't put the ego in check long enough to do the comeback. Likely one of the worst life choices I've ever made.
Now 30+ years later I have a bum leg and I'm back in the pool. Compared to the teenagers I swam next to this morning I obviously suck. Why on earth would I bother to show up in the pool, or god forbid a masters swim meet, when I'm not going to podium?
Some people want to compete. They may compete against the clock, they may compete against their friend, they may compete against the guy dressed like a banana. There is something or someone they want to beat. That drive to compete may not put them under some popular barrier but it doesn't mean they don't strive to hurdle their own personal barrier.
A comeback sucks. That's just the way it is. Toss in some injuries, aging, and it pretty much sucks the big weenie. We're talking Linda Lovelace style weenies here. Top that off with the fact most comebacks aren't successful and you have a magnificent excuse to wimp out. Some folk's egos can't take drop out of hyperspace that happens when things don't go your way. Some folks can't handle the fact that some anonymous prick might say they look retarded.
The rest of us that want to compete make some compromises. You might change the distance, change the goals, change the event totally, or maybe just change the perspective. Nobody can compete at the same level forever, and if that's the expectation then you might as well quit and and save the space on the road for those of us that actually want to try.