I agree that on weekends you will see the most bad players together. That's because most recreational players play during their leisure time. And while some recreational players can be very good at the game, most of them are just gamblers hoping to hit it big by just calling any two.
I think the problem here is that when you have a large pool of donks playing, the variance becomes a lot harder. And this is especially true with low buy-ins turbo games. It's much more like playing a spin-n-go. There's not enough time to wait for premium hands and get value out of them. And even when you do get premium hands, if you get too many callers, better be ready to let go or go busted in trying to win the hand.
I really don't know about the higher buyin games, but as I am a BR nit and I only play within my tiny BR, I do play a lot of low buyins MTTs and SNG, and my best results are week days. I tend to play better against regs than calling stations (not 1 CS, but a table full of them!).
I must admit I am writing this after having lost like ten 45-man SNG in a row. And it was all like WTF, my aces getting cracked by hands like 73o and the like; I even busted short of the final table in two games with decent holdings against totally trashy hands. So well, I think sometimes you get the bad side of the variance when playing against so many fish and sometimes you get the good side. Not my case this weekend lol.