That’s another reason current designs are probably locked in. It’s called being stuck at a local maximum.

I’m not saying what we have is bad, just that the benefit of hindsight reveals some things.

Computing is tougher than other areas of engineering when it comes to greenfielding due to the extreme interlocking lock-in effects that emerge from things like instruction set and API compatibility. It’s easier to greenfield, say, an engine or an aircraft design, since doing so does not break compatibility with everything. If aviation were like computing, coffee mugs from propeller aircraft would fail to hold coffee (or even be mugs) on a jet aircraft.

Aviation does have a lot of backwards compatibility problems. It's one reason Boeing kept revving the 737 to make the Max version. The constraints come from things like training, certification, runway length, fuel mixes, radio protocols, regulations...