Well, it short-circuits the licensing cost argument for rolling your own frameworks, but I don’t think that was ever the real reason why devs love reinventing the wheel.
I think that building frameworks is just a lot more fun than doing what you’re supposed to be doing, which is usually a soul-sucking grind of boring enterprise tickets.
Maybe that’s exactly why they do it. Building frameworks is as customer facing as it gets, because the customers are your coworkers that you can just walk over to and speak directly with.
If one is so insulated from the actual business problem by corporate bureaucracy it may be the only way for developers to do something that matters to someone, no matter how frivolous it is in the grand scheme.