Would it happen here?

[FYSTI]

Quis custodiet ipsos custodes? is a Latin phrase found in the work of the Roman poet Juvenal from his Satires (Satire VI, lines 347–8). It is literally translated as "Who will guard the guards themselves?"

Quis custodiet ipsos custodes? - Wikipedia, the free encyclopedia

This has has evidently been a problem for a long time, as Plato wrote about it. There is no feasible solution to entirely eliminate the problem.

As for full automation, all that will do is move the Human Factors / Terrorism issues to the software engineering cubical & control room.

Before trusting computers, best you read Ken Thompson's 1983 classic paper, "Reflections on Trusting Trust". The memorable quote from it is "You can't trust code that you did not totally create yourself."

In it he demonstrates how to embed nefarious code into the compiler itself, and then compile the compiler from that code, thus removing any traces of the nefarious code as the final binary cannot be validated.

A good read on the issue by Poul-Henning Kamp: The Software Industry IS the Problem

Even if it were possible to work around that problem, It could only be done over an extended period of time as the sheer cost of changing everything over at once would bankrupt the industry many times over.