I agree with you completely. I'm old raider from WotLK times. I actively raided full WotLK, Cataclysm, parts of Pandaria, Legion and BfA. It really started in Legion and got worse in BfA. My guild stopped raiding because we did not have any progress, farm reclears were as hard as second kill and sometimes even harder because of raider turn-around. It was completely different back in the day. Raid was getting stronger every week. You could easily get few recruits who could fail anything but a very core mechanics, die two times and still kill the boss. Current raids are tuned around very top level guilds and developers just don't care about anyone on level below. I changed guild 3 times since Legion, because they just can't survive. It's getting frustrating. I love the game as much as 10 years ago, but I can't raid alone, I have my skill limits and time investment limits.
Classic did not have any significant influence on our raid. Few players tried it myself included, but just to get some classic feels and that's about it.