While not as sexy, you can do:

    <MyList {...{items, selectedItem, onItemClicked}} />

There's a lot of "gets you most of the way there" hacks with JSX that will fill most needs. Where as you can imagine the incredible cacophony of screaming developers who maintain TypeScript, Preact, IDEs, etc. that would be incensed by breaking changes to JSX introduced just to solve some inconveniences.