It's clear that he is a (very good!) full-stack developer. I am curious about where he works, or if he is retired or something, living off investments while working on SteamDB full time.
I think very few people would knowingly turn down income of a million dollars per year. In fact I'd say it's a privilege to be in a position to be able to turn that down. I even see some people here who are asking him to make the income even though he doesn't want it so he can give it to a charity.
I wouldnt be surprised if you could easily work out some sort of deal with Steam, if a game page from your site leads to a buy on their end they give you a small percentage.
I hate ads too. The thing I tried that felt ethical and useful was an affiliate code for related (to the content) products that would split the discount 50/50 between me and readers. I stated this clearly in the ad.