> > We know how to write software with very few bugs

> Do we, really? Because a week doesn’t go by when I don’t run into bugs of some sort.

I mean, we do know how to do it, but we don't because business needs tend to throw quality under the bus in exchange for almost everything else: (especially) speed to develop, but also developer comfort, feature cram, visual refreshes, and so on always trump bugs, so every project ends up with bugs.

I have a few hobby projects which I would stick my neck out and say have no bugs. I know, I'm going to get roasted for this claim, but the projects are ultra simple enough in scope, and I'm under no pressure to ever release them publicly, so I was able to prioritize getting them right. No actual businesses are going to be doing this level of polish and care, and they all need to cut corners and actually ship, so they have bugs. And no ultra-complex project (even if it's done with love and care) is capable of this either, purely due to its size and number of moving parts.

So, it's not like we don't know how to do it, but that we choose not to for practical reasons.