Unless your webcam is made by microsoft specifically for your os (vista/xp/etc) then it is not microsoft who has to supply the correct drivers to integrate well with explorer.
That's exactly the point. The end-user doesn't care who's responsibility that hang is, they bought the hardware and software together and when it hangs, it's Microsoft's fault. Even though we know it's actually J Random driver programmer who wrote the bogus code.
Apple's stranglehold on the hardware and software irks my hacker sensibilities, but it's the key to a much better user experience.
