There are no limitations on a Mac due to hardware, and never were. The problems have always been software related.
There are games for Mac, the problem is that many game developers use DirectX, which only runs on Windows, when similar libraries (like OpenGL) are available and are usually cross-platform (running on Windows, OS X, and Linux). Many "mainstream" PC games are either co-developed for both platforms (Anything from Blizzard), are ported from the PC version, or use a system called Cider, to basically run the same game on the Mac. Then again, there are many games that are Mac only (or were until reciently) that are often more complex than games on the PC. Also, games like Marathon and Halo were originally going to Mac-only titles (the former was for many years before being made available for use in Windows).
The Major Software Suites exist on both systems (MS Office & Adobe Creative Suite) although each have components that only work on one platform or the other.
TEG