It's cool to see a novel idea like this get prototyped and then opened up for discussion.
As others have hinted at, this feels like jQuery with different syntax and more limitations. In its current form, I can't imagine choosing this over jQuery (in part because I already know jQuery, and in part because the limited reach of your selectors feels like it would be a roadblock very quickly).
Perhaps you could reshape this to be an extension of jQuery, where this alternative jsx syntax is available if you want it, but the full power of jQuery's selectors is also available (without having to mix two libraries with overlapping purpose)?
That aside, I can't imagine abandoning React for this. That would feel like a step backwards to me. IMO, the most valuable thing React brought to the ecosystem is a simple way to make reusable components. Much of React's convenience is because of its functional nature: each component instance has an isolated scope/context, making it easy to reason over the behavior of a small widget without worrying about external effects from the larger application.
From what I can see in your examples, you're relying on things like global identifiers/keys, which I think leads to a mess in a large application. Take your counter example: what if my application needs 5 such counters? Can I do this without significant code duplication? I could probably wrap it in a function, but I'd likely need to pass in some unique id to distinguish between the 5 usages. This is a huge part of what React does for you, just keeping track of which component instances go where in the DOM (without needing DOM `id`s everywhere).
It could be that I'm missing something. It'd be great to see some larger examples of a more complex application with widget reuse, to see how that feels.