Solar panels are cheap and batteries are easier to build because they're already taking advantage of economies of scale and aren't in the R&D phase still.

The viability of fusion has been centered for a long time around getting more power out than you put in and once that marker is met it's viewed as the last giant hurdle in the way. There's still plenty more R&D that needs to be done before it can easily / readily scale though.

It's where nuclear was in the 60s basically. Even if it only ever gets to be comparable to nuclear in terms of costing but with none of the hazardous byproduct, it will come out ahead. When you consider the environmental factors involved in battery production it is pretty clear that fusion at least has the potential to be the cleanest sources of energy. Whether it ultimately gets there is another question.