[not_me_ever]

Yes, they do crash, but they never produce wrong results, and that is exactly what they were built to do. And don't forget: These things pre-date the internet, so even thinking about random strangers having access to the network was unthinkable.

Back in the day all the essential software, e.g. flight control, which still largely runs on S/360 today, had to be proven to be correct. There are mathematical concepts/processes that allow that.

The firmware is proven to work correctly. The compiler is proven to work correctly. The OS is proven .... I guess you get where this goes.

The problem is: Nobody today even wants to learn "how to prove software" anymore. I tried to teach a class at my University a few years back, and 12 out of 12 students dropped out in the first 3 lessons. My usual dropout rate is close to 0%.

For non-essential software you are probably right. After 60 years of development all the bugs are gone; Plus the developers know their machines (hardware & software) inside out. No chasing after ever changing platforms, standards, APIs & SDKs.