A future where fusion and solar are the main energy sources we tap into would be beautiful, but to get to that point we are still going to burn a lot of fossil fuels to sustain the current modern amenities we got used to. The question is: how much longer do we have to completely shift our energy dependency? The clock is ticking at a very fast rate, we are not doing enough to be independent from our energy needs supplied from fossil fuels.
Believing that "someone will eventually figure it out" is a form of illusion of continuity, there's nothing in the Universe guaranteeing we will continue human advancement, there's no continuity if we don't work for it. Working for it means: facing that we are in very uncharted territory, which as far as we can predict seems to be leading to a catastrophic outcome.
The "long run" part depends on changes to be done right now to allow a "long run" to exist, if we continue the path we are there's absolutely no guarantee there will be a long run where solar and fusion are powering civilisation...