It's also the thinking that got us Doom. ;) There are use cases where performance trumps security; the only issue here is that "multi-app semi-trusted computing environment" isn't one of them.
I don't think the parent is claiming there are, the point is that Doom wouldn't have been possible without coding with performance as a priority, but that's "ok" because in a lot of applications there isn't a permissions differential to worry about.
Interested in details about this; where were Doom's major security issues? I love reading about Carmack/Doom development in general, maybe I've missed the part where caution was thrown to the wind and security was ignored.
Seems like there never were security issues. At least, none that were talked about widely.
I think that should be expected for a single player game.
Almost all games are hack-able in some way of course but hacking a single player game is mostly an exercise in replay-ability.
Which makes me wonder if the non-clearing memory issue exists for the printer's video driver and whether that could be used to retrieve something like a saved password or ssh key.