but when my tools fail I guess I'll be screwed :(

First off, good for you. You have more sense then most ever will.

Second you touch on two important things. The first is the level of complexity we've hit in society where when tools fail you can't make new tools yourself (in most cases). Boot strapping is very difficult for a lot of what we own. It's a difficult thing to balance, advanced technology versus end-user maintainability.

The second thing is how a lot of common items fail in fairly set and easily repairable ways. Microwaves is a huge one, most people toss them when they fail because it's "cheaper to buy a new one then get it repaired." Well most of the time it's just a blown fuse, 10 minutes with a screw driver and a new fuse it'll be fine again. But hey, don't let ten minutes stop you, much more economical to spend the gasoline to drive to a store to buy a new one, right?

I didn't see that twist coming. I am capitalism's bitch.