888 doesn't get a whole lot of traffic for MTTs really. There's not enough running every hour for any serious MTT grinder to put in volume there. I think the last time I played on 888 they had a few $1-$10 MTTS, a $22 and a $109 in the space of 2 hours.
The Hot $44 on PokerStars has a $40K prizepool - The $35 tourney you mentioned on 888 has a $3500 prize pool. No brainer which one to play really.
I expect they make enough money from the casino/sportsbook side to cover MTT overlay.
Bit of a common misconception here imo. Yes, I realise that you can win more for 1st, but in the long term that's not as important.
The GTD needs to translate to an increase in ROI or that to hold true. If I buy in to a $44 on 888, and estimate my ROI to be 50%, and buy in to a $44 on stars and estimate my ROI to be 40%, then I'd rather play the former, even if it's significantly less up top. We will make FT's a lot more often afterall.
IN the specific example you gave, with the "Hot" being a turbo, I can almost guarantee you'd have better ROI on a reg speed on 888 of the same buy in. And you can't even make the hourly argument, because they'll probably last about as often as each other.
Adding sites with smaller fields is a great way to reduce variance.
As for the OP, there were DC issues yesterday on 888, so perhaps that put people off. They were resolved after ~30mins. But it might have ended regs sessions early.