We can build reliable software when we want to. It just has limited scope and/or undergoes more expensive development procedures.

It is easy to build a finite state machine for a dishwasher that is fairly reliable. Likewise, consumer jet code that hits safety considerations is heavily tested and audited...and the FAA cares about it whenever it causes a plane to crash, leading to a lot of regulations on how the code is vetted.

Sure, software is everywhere, but the physical properties of hardware are fundamentally different when it comes to QA, risk analysis, general testing.

But when all your hardware has firmware, you've lost that advantage.

Depends how complex the firmware is.