Wishful thinking is not idealism. It is self-indulgence at best and self-exaltation at worst. In either case, it is usually at the expense of others. In other words, it is the opposite of idealism.
Every time you look up at the sky, every one of those points of light is a reminder that fusion power is extractable from hydrogen and other light elements, and it is an everyday reality throughout the Milky Way Galaxy.