Ever think that Google is doing all this just to shake people up and soften them for the "big kill".
Google just released Google Checkout. No one I talked to is using it, there's really no reason to.
Google offered a small incentive to use it with Adwords and have it reduce fees a small bit. Still no interest from me and others.
Perhaps Google expected this, perhaps they were surprised.
Now, we know Google is moving to Cost per Action. But to truely have real CPA then Google needs all sorts of info about your business. Most of all they need to know for real when a sale is made.
The only feasible way to do this is Google checkout or some sort of payment processor tie-in. Otherwise it would be easy to obscure sales to get lower rates.
But who in their right mind is going to give Google that kind of access?
Well, if you're making $500,000 a year with .10 bids and Google starts charging you $10 a click...you'd sign up for CPA if Google promised you the ability to get back in the game.
Perhaps Google is just blackmailing people by holding their campaigns "hostage" and CPA/Google Checkout is the ransom.