Nobody wants their privacy invaded, but they do want cheaper products. In theory better targeted ads allow a company to spend it's advertising budget more effectively. Selling more products for the same amount of ad cost should allow for cheaper products.
I'm sure some companies will not pass on the savings, but I believe economic theory says the market as a whole should.
If the savings are enough, some people may be willing to give up some of their privacy in the name of cheaper products.
How much more do companies make? Is all this invasive tracking really necessary in order to keep websites like Google and Facebook free? Is it worth saving 10% (or whatever) on some product?
Unfortunately the decision is forced upon everyone by advertisers with little thought to allowing for an informed choice (or any choice really).