That's actually a great question. Yes there are a ton of OW swim events, even pro ones(as very cold temps) that allow wetsuits. But I believe that push came from triathlon. We made the wetsuit normal, we made it great, and we made it fast. All that pressure spilled over to OW swimming, a sport that actually had a rule against them, and was militant about it.

It is kind of like aero bars, we had them years before cyclists, but at some point, they just couldn't ignore them and the advantage they provided. Had we not been around as a sport, not sure if cyclists would even be using them today. It really was a stodgy and set in stone sport. They might have index shifting, maybe clip less pedals, and now electronic shifting, but those are all improvements on what existed before. Aero bars were alien to them, and even when they were proved to be a huge benefit, a lot went kicking and screaming over the next couple decades.

And wetsuits were really pioneered for surfing, along with diving. And funny to note that surfing wetsuits have gotten a lot more like triathlon wetsuits over the years, I tell guess even surfers like a nice fit that is comfortable. Those suits I wore in the 60's and 70's were pretty horrible, but they somewhat worked, and no one knew any difference..

There is a big difference between wetsuits and aero equipment. Aero equipment reduce drag, wetsuits increase buoyancy. Wetsuits are more akin to adding a motor to your bike, it increases power.

I mean, it's pretty obvious that the speed/buoyancy advantage drives the use of wetsuits in triathlon. I don't get the "wetsuits are a crutch, blah blah blah" argument. Maybe, for some, they do need a wetsuit to even finish. But for myself and many others, its the advantage. That's like showing up to a time trial and complaining because you see too many deep dish wheels and aero helmets. It's part of the sport.

This is not like aero. People are not like "It's so windy. I can't use my disc wheel. I'm afraid I won't be able to finish the bike". //

Of course it is, just go back and look at all the bike splits that just make the cutoff by a few to maybe 20+ minutes. Without aero, they would not finish the bike, and thus, not be going onto the run, same exact thing..

it's cultural/social.... as soon as one of those guys who cares about racing gets beaten in a race by a guy with a wetsuit, the rest of the swim peleton will probably adapt.