For a startup to have a chance at success, it must have founders who are willing to take risks, face skeptics about the viability of their idea, prove their idea, and then prove their idea can be monetized. And sometimes shift their focus or bifurcate it. Sometimes, a startup has a primary goal (say, making commercially desirable electric vehicles), but as success accumulates, other (related) commercial avenues may present themselves. The pandemic certainly has seen agile startups shift and make the most of the situation. And while Elon Musk's idea to leverage its battery technology to achieve a successful 'renewables-plus-storage' model is disruptive to the current 'normal', it is not too early to consider as a serious option. The 'norm' is always changing, and commercial markets are the best testing grounds for what is likely viable. And good startups are great at changing the norm.
It is impossible to say that Elon Musk's idea to 'disrupt' the existing U.S. power system will take hold or prove viable. But he has an idea to make the power system better, so hopefully the 'powers that be' give it a chance. To the extent they should have a say.