Does the world need the "uniqueness" of 40 similar web frameworks?

As long as there are standards, yes, why not. In Italian we have a saying: il mondo è bello perché è vario. The world is beautiful because it’s varied.

Imagine if we have 40 variants of assembly. Would software development have developed at the same pace?

Personally for me, I am much less interested in the implementation in frontend and more interested in performance, accessibility, responsiveness, etc.

Frontend frameworks are just means to an end. If we can standardize to one, then I will have more time to focus on the more important parts.

the world certainly needs novel ideas. maybe eventually we'll come up with a web framework that doesn't suck - or rather we'll realise that Django had it right all along for all these years.

Since a good LLM can handle any of those 40 web frameworks, I think having 40 web frameworks is becoming less of a problem than it used to be. Actually, implementing ideas in an individual manner will become easier. Remember the Bazaar and the Cathedral? The Bazaar kind of failed on the client side, but LLMs may revive it.

Perhaps not but the world does need the uniqueness of 40 different people who each made their own web frameworks

Perhaps not if the one framework we ended up with was a good one …