Most people asking how to “build a their own engine to build a game” should be discouraged from that. They’re probably either not thinking deeply about the trade-offs or are not in a position experience-wise to do so. Just because 0.5% should be encouraged doesn’t make the common response that you see wrong as a default.
(Someone who shipped a game on a custom engine 25 years ago; would not do the same now.)
> Most people asking how to “build a their own engine to build a game” should be discouraged from that.
Why? You didn't even ask why they want to build their own engine. If the purpose is to learn their underpinnings, then they should not be discouraged to do so. This telling people they should be discouraged to build engines is just stupid and unfortunately very common based on gross generalizations of what "most" people "want". Why not ask what the person's motivations are instead of assuming they are a brain-dead code-camp weekend motherfucker who all they want is to make an "app"?
(Someone who shipped a game on a custom engine 25 years ago; would not do the same now.)