It's true that many PC games release several patches, but what these patches actually do is completely different.
Most PC games(good ones anyway) have nearly all the big issues fixed before the game is released, and any that aren't are fixed in the first patch. Then minor bugs or balance tweaks will be fixed in the next couple patches as they are found. They usually do
not (a) introduce NEW gamebreaking glitches, (b) leave broken parts of the game everyone complains about intact(i.e. psychic cpu). Usually with a (good) PC game the game is at least 95% perfect by the second patch.