In his keynote announcing the Powerwall, Elon Musk made a quip that sounded familiar:
We have this handy fusion reactor in the sky called the sun, you don't have to do anything, it just works. It shows up every day.
It's a great line. Others have said pretty much the same thing in different words over the years; Joe Romm of Think Progress used a version in an article complaining about fusion reactors in 2012:
I am a big proponent of harnessing the power of fusion — from 93 million miles away. Fusion is done by our sun really, really well and for free. Here on Earth in reactors … not so much. And so the famous saying, “fusion energy is fifty years away — and always will be.” ....Unlike fusion in the past three decades, renewables, especially solar and wind, have seen major technological advances, a steady drop in cost, and major innovations in manufacturing leading to commercial products.
It was probably said best by architect William McDonough in 2006, quoted in TreeHugger:
Don't get me wrong: I love nuclear energy! It's just that I prefer fusion to fission. And it just so happens that there's an enormous fusion reactor safely banked a few million miles from us. It delivers more than we could ever use in just about 8 minutes. And it's wireless!
And they are all right.