There are speculations, and they are not only untrue whether Google is better off if Microsoft/Yahoo did not proceed with their merger.

Since there is probably already some amount of tension on both sides, sometimes the way a company can actually become uncompetitive is when it tries to digest another big company, in which for the next two years, they will have their hands full integrating the operations.

This happened when Compaq got DEC, and when HP got Compaq.  Was Google really smart by offering to help spoil the deal?

Google execs hope for long-term ad deal with Yahoo - Yahoo! News

Google Inc.’s top executives expressed hope Thursday that the Internet search leader will be able to form a potentially lucrative advertising partnership with Yahoo Inc. — a deal that would lower the odds of Microsoft Corp. renewing its attempts to buy Yahoo.