It is unlikely that the Mac will have more games than PCs in the near future. The gap between the amount of games available between the two platforms might narrow in the future, but in the foreseeable future, the PC will be the leader in this area.
This is mainly because most game development houses use DirectX - application programming interfaces developed for Windows by Microsoft. Microsoft does not port these APIs to other platforms, and games written with these APIs are very difficult to be ported to other platforms.
There are some open-source projects going on right now that would try to wrap these APIs and map them to cross platform equivalents (such as OpenGL), but these are bleeding edge projects, and it'll take time before they're ready for primetime, and then we'll have to see if programmers would embrace them.
However, Apple does have pretty good foundation for gaming in OS X right now, with its implementation of OpenGL.
-B