Evo,
Yes, you've taken the bait
There is room for everybody, of course. Just as there is room for an owner of an antique car - nobody is suggesting that he should not drive it a few times a year just because the dual carriageway he drives on was paid for (in part, perhaps) by people who drive to work every day.
But try this: look at your local airfield (I could have picked a bad example but this is the general idea) and find out where its money comes from. Then look at how many people are doing PPL training (the CAA website has some figures but not very recent ones; for those you need to go ask a few school owners, privately...).
The traditionalists will indeed kill off GA. Not intentionally and not even through their presence. They will kill it off by ACTIVELY ensuring that, at every opportunity, it continues to look like a WW2 movie, with WW2 aircraft, with WW2 navigation, you name it. This prevents new people who can actually afford to fly fairly regularly being attracted.
But nobody is aware of this, because these people don't walk in, look around, say what they don't like, and walk out. What they do is they look in the sky and see WW2 planes rattling around. They sometimes drop in at the local airfield, see more WW2 planes rattling around; they politely smile and walk away.
Your sailing comment is interesting - why do you think the less affluent have dropped out of it?