2050 is still an awful long way away. Note the effects of pollution in a closed box are exponential.

Every forecast of future damage effects has so far turned out to be an underestimate.

Further, the effects are far wider ranging than most people expected, especially concerning economy.

It takes only a few years for a whole country to go solar.

Let's say somehow fusion becomes reality.

Then what?

The creators of fusion power gain and retain absolute control of all energy on Earth.

Even if the creators of it wanted it to go "To the public", of course it wouldn't, because there are folk who would take control of it to become rulers.

That will make most people slaves, a lot more so than they are already, it seems to me.

Is that really what we want?

If not, then we should hope we become reasonably solar powered long before any fusion "success", because solar power is distributed by nature, and generates no pollution. In fact work done by it (To create and consume hydrogen as a clean fossil fuels substitute, for example), cleans the air, and even transports water.

In that case, authority for power would most likely be with our local community solar farm owners.

Not perfect, but infinitely preferable to a one-world all-powerful, fusion powered authority, I believe.