I think the biggest channels I watch have under 4 million subscribers, and most of my channels have less than a million. I've never watched the big channels, so I don't really care.
A while back, YT asked me about turning on my watch history, but I didn't know it was off. I don't know what that was about--I think they changed something--but my knee-jerk reaction is to NOT do what they want me to do, so I left it off. Now I just watch whatever is new from my subscriptions, and don't have any suggestions cluttering my front page, which is a much better way to use YT, imo. So, thanks, YT.