In terms of sheer numbers, I'd guess you are right: more Win32 applications have been written since 1995 or so than there are apps for iOS. Especially if you include in-house software.
In terms of applications to do something most people want to do, which is a subjective measure I admit, iOS may have the lead. Particularly so if you look for software that's optimized for tablet use: there are a lot of very capable Windows programs which are rather less usable on a tablet than with a physical keyboard and mouse, whereas iOS apps are all designed around touchscreen use.
For example, I've been looking for a map program (similar to Google Maps) that runs on a handheld Windows 7 PC with attached GPS. It's surprising how few choices there are that do the basic function of showing your GPS position on a map, and aren't some crusty thing last updated in 2004. True, if I included Windows 8 "Metro" apps there would be a wider choice, but still it is dwarfed by what you get on Android or iOS. (FTR - in the end I went with Anquet Maps for hiking maps and Mapfactor PC-Navigator for city use.)
The biggest annoyance with the AT keyboard is the lack of F11 and F12 keys, if your applications use those (e.g. to step into statements in a debugger). The Esc key being on the numeric keypad is also odd but you get used to that.
There's also the 122-key Model F 'aircraft carrier', which has a much more modern layout, close to the international Model M layout.
But if you do prefer the US Model M layout (de gustibus non est disputandum, after all), then here's a way to modify the PC-AT keyboard: http://geekhack.org/index.php?...