You're making the same mistake as people who ask how ancient buildings we're built that they stand so long. You don't see ancient buildings that crumbled down, and you don't remember a LOT of old software that was complete crap. I've used computers since 1995 with DOS 7, and my memories of these times aren't so rosy at all.

This also doesn't consider all the crap software you get today, so you are making the same mistake as well.