I once posted the specs of the machine I play Mame on, and was told it was way above spec for what most people have. That surprised me. Hardware isn't expensive these days, and there comes a point when you simply should upgrade. I mean, at least buy a new machine every ten years.
From what I can make out in this thread (which I should probably have stayed away from), there are people generally missing the point.
1) You never have to upgrade Mame. If you have a version that works for you, then keep on using it.
2) Mame exists to archive/preserve arcade games. It does not exist to archive/preserve old PC game controllers, Direct X versions, OS's, drivers for peripherals, etc. There is plenty of equipment that does work, so if you need something, go get it (or not, your choice).
3) Not all compatibility issues are controlled by developers. Some are dictated by tools and OS's. Ongoing Mame development must keep up with the times, or Mame itself becomes obsolete and broken - thereby becoming a victim of what it seeks to solve.
4) It's not clever to have old hardware.
5) Maintaining old code takes development cycles away from improvements. As far as I know, Mame developers are volunteers. While giving opinions is fine, I do find some of the rhetoric a tad aggressive.
6) Mame is free. If you choose to not use it because you're holding on to a controller that's 10+ years old then you're just hurting yourself. It's your choice. As a free bit of development is it really reasonable to expect the devs to maintain compatibility to early versions of Windows?