The only catch is.. who is going to replace them? AltaVisa? Lycos? WebCrawler? Cuil? (That last one - not impossible, but unlikely). You need tens, if not hundreds of millions of investment dollars to get anywhere near the level Google is at - *even* if your algorithms are vastly superior.
We need to seriously consider the possibility of the "pro-" web changing drastically in the next few years. It's quite likely that as more and more small players die unable to compete with Google playing squarely against them, the surviving few will go through a very fast DNA mutation process, forever changing the nature of what constitutes "professionally made web sites". (Amateur sites like blogs and niche resources can probably remain roughly the same as they are now).
For the surviving species, I see, at the minimum, a move towards more content permanently closed off to Google and other spiders/aggregators/scrapers. Probably more and more AJAX and images, as well as more stuff behind password walls. More prominent site brands and more custom-made-for-this-demographic web sites promoted exclusively via social networks. In other words, if the old strategy of opening up as much content to Google as possible and letting anybody have it becomes your delayed-action poison pill, rethink and reload. For the rest of us (you lucky folks with day jobs), sit back and enjoy watching web evolution in a fast-forward mode.
It would be interesting to see if some (professional/legitimate) webmasters actually try to unionize to defend their rights together. It's difficult to do when you are millions, but once only a few thousand are left standing, suddenly it's easier to find common ground. This could actually lead to a more transparent industry.
Finally (have you thought about it?): why is having our pages in Google important? Visitors, right? And why are visitors important? Selling advertising! Could it be that we've been betting on the wrong horse all along? Could advertising be an evolutionary dead-end? Sure, web sites supported by advertising are doing better than others for now - but so did dinosaurs, by the way... for a while. Until it gets cold and all the food has been eaten by Google.