I truly think it's just because the engineers that started working with node were ... young. They wanted to rapidly iterate, and so crufty old habits like this weren't what they wanted or felt they needed.

What's been interesting is watching these devs age 10 years, and still mostly decide it's better to start new frameworks rather than treat legacy code as an asset. That feels to me like a generational shift. And I'm not shaking my cane and saying they're wrong -- a modern LLM can parse an API document and get you 95% of the way to your goal most of the time pretty quickly -- but I propose it's truly a cultural difference, and I suspect it won't wash out as people age, just create different benefits and costs.