The Firebird
Adventurer
There is quite a bit preventing people from using older editions, because network effects are very strong in RPG land. Making lots of these little changes to the current ruleset requires either DMing oneself and presenting the players with an exhaustive list of houserules, or joining as a player and presenting the DM with a very long set of asks. Neither are great options, and doing so as a player will have people questioning if you're a good fit.See here’s where I get off the train.
If you want to use older options, just use them. There’s nothing stopping anyone from using any options. You want to use 2014 style racial mods? Knock yourself out. You want to have a ranged fighter in 4e? You absolutely can do that. You want to play a fighter magic user in 3e? You absolutely can.
It’s utterly baffling to me why people freak out about changes to the game. It’s your game. PLay what you want. Why the incessant need to pee in other people’s corn flakes constantly?
But nope. We must resist all changes with the fire of a thousand suns, spending years poisoning any attempt at compromise or live and let live.
It really is exhausting.
As for finding games for 3e or 4e or AD&D or whatever, the player bases for these are going to be much smaller. If you've lived in the same place for a decade, and it's got a large population, it should be fine. But if you're moving around constantly or you live in a rural area, then its going to be harder to meet people. We're not playing solo; building an RPG group takes time.
So for a lot of people, changes made to the flagship product are going to appear in our gaming whether we like it or not. That's a good reason to be concerned about them even if we would much prefer a different game.