In your mind, how many years is a few years? I watch Formula E, but it's hard to imagine it becoming the pinnacle of motorsport anytime soon.

Formula E's definitely made progress: e.g. they no longer have to run two separate cars just to finish the race, and they are decently quick. But they're still pretty far away in other aspects: 45 minute race, on temporary circuits purposefully designed with many tight turns to allow for braking regen. Battery technology has to improve quite a bit if you want to see electric cars turning laps at Spa at standard race distances.