Even so, "system matters" is a phrase I think is more applicable to wholly different systems. D&D vs WoD vs RQ, &c. Excepting 4e, it is relatively easy to convert materials from one edition to another. 4e's engine is sufficiently different that I think conversion is quite a bit trickier, and system may matter more in that case.
I think it depends. You can get some games that are quite different, and yet the mechanics are really similar. I'm thinking of BRP based games. So you see that DNA in Runequest on to Call of Cthulhu and then in modern games like Mothership.
And sometimes, it's the small changes that will be the hardest to handle. My players don't bat an eye at shifting from 5E D&D to Blades in the Dark, for example, but while playing 5E they still sometimes say things like "I'll take a 5-foot step" or the like. Plus, they have multiple versions of the same spells that are slightly different by edition all rattling around inside their heads... so those subtle differences are sometimes a pain in the arse.
I cannot speak for "we". But for myself.... I will play virtually any game, D&D or otherwise, given a good GM and players at the table. There is no version of D&D that is a flat no, for me. However...
2e and earlier are all kinda clunky, imho, largely because they date from before the world knew much about RPG design. 3e got a handle on design, but there are too many fiddly bits. 4e is a decent enough design, but still has a lot of fiddly bits, and some assumptions (about map use, f'rex) that I'm not on board with, and find it a lot of work to remove.
5e is using design principles carefully, with fewer fiddly bits and assumptions I'm not happy with. It hits a pretty cool sweet spot that I enjoy.
I meant "we" as in the people who play/run 5E... I expected everyone to only answer for themselves!
My feelings on editions are very similar to yours, if not exact. I think B/X is solid, especially when cleaned up as Old School Essentials. But yeah, AD&D is clunky. The 3E games are over wrought, I'd say, which was a big desire for me to move away from that, as much as we loved 3E at first, it just got out of hand. We played 4E for a short while, and though I liked it from the GM perspective, my players were not crazy about how it played. So we then switched to Pathfinder. As I said, I was kind of frustrated by 3E bloat... at first, Pathfinder seemed a reasonable alternative, but that quickly got even worse than 3E had been, in my opinion.
So 5E was actually a relief for me. It was simpler to GM, had far fewer player options but enough customization to keep my players happy. I was really happy with it.
Over time, that luster wore off. I've also played more of it than any other edition in many years, and having a more complete view of the player experience hasn't helped.
But I still enjoy it! I think it helps that I play it with my longstanding play group, which is made of friends dating back to my childhood and my earliest days with RPGs. I think that's a really big factor for me... we know each other really well. They know how I GM and I know how they play, and so we can use 5E to get to where we want. But... if I was playing with new folks, I'd be a lot more hesitant about it. To the point I'm not even sure I'd want to run or play it unless it was the only option.
As long as my friends are interested in playing it, I'll continue to do so. I will say that I'm not really happy with what I've seen of the playtest material for the 1D&D change. Those seem more like a shift toward the 3E era stuff... so I don't know how willing I'd be to go back to that kind of game. We'll see.