Technically. But

1) Your "templates" look like this:

  React.createElement(
    "div",
    null,
    React.createElement(MyComponent, null),
    React.createElement(
      "ul",
      null,
      React.createElement(
        "li",
        null,
        "Thing 1"
      ),
      React.createElement(
        "li",
        null,
        "Thing 2"
      ),
      React.createElement(
        "li",
        null,
        "Thing 3"
      )
    )
  )

2) Since things like decent state management don't come in the box, you're almost forced to start including other modules, which pushes you back towards a build system.