There was an interesting interview with a long timer with google on a podcast I listen to (freakanomics?) where the concept of ads came up. Apparently very early on google did the analysis and found that google search provided something like $50 (can't remember the exact number) of actualizable annual value to a typical user. Which is to say they could charge around $5 monthly and it'd still be worth it for most people to pay. But the ads. They could make way more than $50 per user just during the christmas season alone. And so it was a no brainer for them to go with ads (despite anti ad sentiment being a key part of the papers that led to the creation of google...).

So, to answer your question. I think we do value our time less than advertisers do. Worse, is I suspect your eyeballs becomes more valuable to advertisers the more your willing to pay to not see ads...