The majority of American picked Gore—the climate candidate—but got Bush—the fossil fuel president. The majority of Americans picked Hillary who, whatever her flaws, was not Trump. We got Trump.
Demanding unity is simply not realistic. And, as I have shown, a mere majority is not necessarily enough. Again, I agree with Spider-Man’s aunt—with great power comes great responsibility.
That said, even without being united, ordinary people can do more. However, because we do not have power, our strategy must be brilliant. One example is that outlined by Andreas Malm in his book How To Blow Up A Pipeline. He outlines a plausible tactic that could start with a few dozen people—sabotaging the infrastructure and products of the fossil fuel industry. His idea is this: if fossil fuels became a risky and unprofitable sector, investors would flee and alternative energy would have a better change to grow quickly.
I also agree that people tend to simplify and, like you say, Elon Musk has made real efforts to grow solar and do other environmentally valuable things. I’m not too worried about his feelings being hurt, though. ;-)