We don't know how much of that revenue, however, will reach Microsoft. Among the many, many deals MS made R*, they may have given them a very low per sale royalty rate. Typically, royalty rates are very high (~15-20$) per full price $60 game.
If you compare this to last generation, then there is absolutely no question that this was a huge loss for Sony. However, looking at this generation only, I think Sony benefited more from GTA 4 than Microsoft did.
Think of it as an A student from grade school that had been getting a D overall his freshman year of college, and is now improving that grade to a C, and he looks like he could further improve it. GTA 4 may be another bump in popularity for MS, but it's a bigger boost for Sony who is in more need of games on their platform.