At Google, the answer is a firm no. Someone else commented on the "we just spent a million dollars training them, why would we fire them now?" quote which is commonly thrown around.

People get fired for leaks and being intentionally malicious, not mistakes. Even expensive ones. [besides, a big outage is usually caused by multiple smaller issues if your systems are sufficiently reliable. Also, read the SRE book about "blameless postmortems"]