> I am one of the people who irreconcilably disagree. I think svelte and solidjs are - obviously - technically superior.

I don't really think that React is necessarily the best possible library, but there is certainly more to a UI library than simply compiling out the need for diffing. For one thing, I find JSX to be a relatively unobtrusive addition to the language. It is implemented by a variety of things and is a pretty simple transform as far as things go; basically pure sugar, it's possible to avoid it if you want. It could be better designed than it is, but I think it's at least sufficiently general - it is feasible to say, use an alternate library with JSX, like Preact.

Svelte on the other hand by its nature just simply requires a more complicated compiler step to work and deliver on its promises. That's a trade-off. Whether you think it's worth it is up to you, but presenting it as an objectively technically superior design is disingenuous. Superior how? Runtime costs? Sure, but it does beg the question how much. Will a well-optimized Svelte app feel much better than a well-optimized React app?

> The amount of hype around it made it really feel like the next big thing.

We are a really long way away from the hype of React. I would argue that hype stopped carrying React a long time ago. Momentum? Sure, but if something was truly dramatically better, then I think it would have a fair shake at beating out React.

The problem is that the web isn't microbenchmarks and developer experience does matter to some degree, so the trade-offs that seem so good on paper don't always pan out.

I'm not a hater of Svelte. On paper, it is a very elegant idea. However, when I actually tried to use it, I genuinely came out feeling that it was simply not for me, and the benefits it has are not enticing enough for me to continue experimenting. My React apps are not particularly slow or bad at handling huge amounts of data. (One of my apps has no problem handling a file grid of over 1 million items, and in fact, I run into issues with browsers not being able to handle a large enough scroll area long before performance of my React code is a problem. That is good enough for me.)