Is adsense Unrivalled or "Affiliate Programs" is the only one competitor? What do you think? As you know, losing adsense account is a common fear. Webmasters stop developing after losing their account or go on with Affiliates? (or anything else)
It really depends on your niche, but usually when you get up into the really high traffic, Adsense is worthless
I think adsense's targeting of Ads and the freedom to place it anywhere is what makes it such a good program for publishers. And yes I think alot of publishers fear losing it, and could be a major setback and some possible might just stop developing websites..
If you are in a right niche, you can make lots of money with AdSense with a decent traffic. Is it unrivalled? Yes, it is. I used to run my own mini ad network using php ads software on my sites but it was too much work for me. Setting up account, checking banners, etc. But AdSense now takes care of every thing. I have only two affiliate banners that I am running for the last two years. Long time ago Andy Dunn used to publish a news letter, mainly catering to adult webmasters, and I was an avid reader because it was full of very informative online marketing tricks, scripts, and other tit bits . I learnt a lot of stuff from his news letter. One the thing I learnt is that if one person would pay you to take care of all your ads, go with that option rather than dealing wiht dozen advertisers. That was before AdSense and Google. Of course, there is this risk of "putting all your eggs in one basket".