I don't know much about fusion. But it seems to me that the main problem with fission today are the time, capital and expertise required to build the plants.

I don't know much about fusion. But it seems to me that the main problem with fission today are the time, capital and expertise required to build the plants. Even if we had a commercializable fusion reactor prototype today, would it be really easier to deploy at scale before we hit 2.5 degrees of global warming?