We need a little more than that, though. You can accomplish that right now with JS template string literals and innerHTML:

  function myComponent(props) {
    return `
      <div>
        ${props.name}
      </div>
    `
  }

  ...

  document.body.innerHTML = myComponent({ name: "Bob" });

The problem is that it always completely obliterates the DOM, instead of changing just the parts that need to change. The browser, of course, has plenty of information with which to do that in C++ instead of requiring the use of something like React. But for some reason it hasn't been implemented.