It’s not complicated, it’s all about the arithmetic. If the user can supply enough hashpower to pay the site more than the ad then they can. I am skeptical that

It’s not complicated, it’s all about the arithmetic. If the user can supply enough hashpower to pay the site more than the ad then they can. I am skeptical that ads would be less profitable - but some sort of credit system where built up mining could escape future ads certainly isn’t off the table. I really don’t know the logistics on ad revenue.