Ok, for the record, I haven't worked at a FAANG company so the stakes weren't as high. Just video game studios, so million dollar companies not billion.

Even on our systems, we had so many redundancies and test servers run, that even when a mistake did run through (which was exceedingly rare, given the testing), the roll back was quick. A single dev, especially a new hire, was unable to make multi-million dollar mistakes. It had to be several systems to fail, in order to be released to the wild. I can't believe any of the FAANG companies got to where they are with such a "cowboy" attitude as to say, "it's your third day, push that untested code straight to prod".

Edit: autocorrect hates me