Sure, I'll agree that they did break down. Everything does at some point or another. Back then it was easier to repair your equipment and you had the right to. That's why they were "built to last"

Then, as time passed, that changed. It became difficult to find the necessary parts for repairs.

Example: My father is a heavy equipment mechanic. I'd say somewhere in the last ten to twenty years, his suppliers started to refuse selling specific parts he needed because he's an independent.

He also described to me how some jobs he takes today feel like he's handling a bomb. If he so much as trips a stray sensor, a representative from the machine's manufacturer will come sniffing around the yard to catch him.

Then there's the knowledge required to perform the necessary repairs. The common sentiment I hear from people is that it's cheaper to replace than to repair. They're not wrong, however this way of thinking demotivates the need to learn how to repair it.

So yeah. Those built to last machines have broken down. Knowledge and parts for them have become difficult to acquire, however an enthusiast willing to put the time in to repair them will have a machine that hums for the rest of their lives.