Google’s concession has made it more difficult for anyone to invoke fair use for book searches. The settlement itself is proof that a company can pay licensing fees and still turn a profit. So now no one can convincingly argue that scanning a book requires no license. If Microsoft starts its own book search service and claims fair use, the courts will say, "Hey, Google manages to pay for this sort of thing. What makes you so special?"
By settling the case, Google has made it much more difficult for others to compete with its Book Search service. Of course, Google was already in a dominant position because few companies have the resources to scan all those millions of books. But even fewer have the additional funds needed to pay fees to all those copyright owners. The licenses are essentially a barrier to entry, and it’s possible that only Google will be able to surmount that barrier.
Sure, Google now has to share its profits with publishers. But when a company has no competitors, there are plenty of profits to share.