This seems like a topic where the often dubious "engineer" title as applied to programming is actually meaningful. Engineer has professional and business connotations that set a corresponding bar for rolling-your-own being a justifiable course of action. Contrast that with programming that is primarily motivated by creativity or curiosity. There, rolling-your-own can still be the right thing to do even if you're aware of a pre-existing thing that's likely better than what you will come up with.