Mainstream
 

I am going to 1 last time to start a niche porn site. The few main streams I tried were on affiliate income. But I think this nitch might work.
But for a mainstream site I want to start, or maybe now 3 related sies.
So from what I see there is PPA or PPC or Revshare, is the Internet way. But people here put up sites and expect PPC, PPS or Revshare and get nothing or supposedly make big bucks.
But if you look back at advertising, prior to the Net, businesses advertised on the multiple impression theory. An insurance agent gave out calendars, keychains etc. Hell, you still that on TV with most ads seem to be for car insurance, wanting to save me $400 a year to switch.
So why should I put a business' ad on my web site, if they get lots of hits/impressions but I get no PPA, PPC or Revshare, why do it? Shouldn't they pay for my impressions.
In the old days, you never saw a funeral home advertise on TV, but the coffee cups, calendars, newspaper ads, ink pens, the little league team sponsership, etc., they put out. It was all about impressions.
Truth is when I do an Internet search, I click on the Google or Alltheweb answers, but I can't recall how few times I click on the Google ads on the right or the paid ads at the top. Usually they have nothing to do with my search question.

companies don't want to pay for unproductive ad space

you gotta click to get paid. Give their site a chance to sell.