Human factors. Developers ship a new OSS framework Z because it makes an extremely subjective improvement on framework X in their opinion. And the process of wr

Human factors. Developers ship a new OSS framework Z because it makes an extremely subjective improvement on framework X in their opinion. And the process of writing Z satisfies an intellectual curiosity to write something from scratch and it also looks great on your resume to have written your own framework. Z framework actually gets popular, other developers, kind of bored at work from using the same tools for ages try out framework Z. And it's nice to try out something new, it makes your work day feel fresh and different and you learn something. Framework Z slowly gets more popular and now it's the hot thing to have on your resume because the smart bleeding edge developers are using Framework Z. So more devs start using Framework Z, try it out on a side project, or a new project. Eventually even the skeptics about Framework Z have at least tried it out and put out a blog post with their thoughts on Framework Z. Framework Z feels legitimized, it's a boon to a lot of careers. Lots more people use it. Recruiters start to ask for it as a requirement. I don't want this to sound cynical, because I think it can sound cynical. I suspect the industry starts from good first principles of wanting to learn new things and try new things and make improvements, and grow themselves. But there is also serious capitalist pressure on the whole system. And a lot of real money on the line, and careers and Twitter followers and conference speaking engagements. So between the good reasons and the bad reasons, in web development in particular, things move way way way too fast for little gain.