So you want to write:
if platform.win_version_info >= (5, 1, 2600):
Is that really much better than:
if platform.win32_ver.version >= '5.1.2600':
There are a few cases with older windows versions where the third component is 3 digits, and it's always possible that could be true again, but I don't think it affects anything you're likely to be checking for in 2014.
If you want some different number... then what? It would be nice if Microsoft had a nice numbering scheme so
Windows 7 was 7 rather than 6.1, 2003 wasn't sometimes 5.1 and sometimes 5.2, etc. But they don't.
Meanwhile, Microsoft's suggested solution is that you not check for version numbers at runtime, but instead check for features. And there are good reasons for that--for example, XPSP3 N has exactly the same version numbers as XPSP3 normal, but if you try to use the new Windows Media APIs, you'll crash.