[dnautics]

> The speed of development was very low,

Not a part of GP's assertion

> and how many people can check the proofs?

it's not necessary, the proofs are checked using automation. I'm directly taking a shot at this assertion:

> Static analysis tooling has demonstrated that it isn’t up to the task

[oscardssmith]

Just because you have a proof doesn't mean it proves the right thing.

[dnautics]

Congratulations. You have won the argument "there is no perfectly secure system", which no one was arguing.