> Just about any reputable sources puts the combined market share of React, Vue, Angular 2+, and Solid well above 80%.

I have no idea if that's accurate, but let's assume for a moment that it is.

- Vue supports JSX, but it is not the default.

- Angular does not support JSX.

- Svelte, which you neglected to mention, does not support JSX.

- Solid does indeed use JSX, as of course does React.

So two out of the five main SPA frameworks don't even support JSX, and another doesn't typically use it.

As I said, you may have stabilised on JSX, "we" have not.