Your argument, if taken too far....

Then don't take it too far.

I have personally seen two very experienced CPAN authors (names almost everyone on this site recognizes, as they've written and maintained code used and recommended countless times) pursue a pointless rewrite of code intended for delivery to a customer the night before delivery.

Did that cost my business something? You bet.

Opportunity costs of reinvention are very real. They don't always happen, but software project management is the art of managing risk.