I don't understand how we're still using fossil fuels. I thought the only thing that would save us from the scourge is if renewables were cheaper, but even with solar being cheaper than everything else, we're still deploying fossil fuels.

Is it because of the interests of fossil fuel companies and their lobbying, or am I missing some economic factor?

Ultimately, the answer is fuel density. So, for long distance untethered travel, like planes. Beyond that, it's plastics production and chemical manufacturing.

We can switch to hydrogen for lots of stuff that requires carrying your fuel on your back, but some things get tougher because the density is just not the same as a hydrocarbon.

These are all surmountable (biodiesel, carbon capture->fuel cycles, bioreactors, etc), but they take time and money.

In the end, what will push us to get there are economic shocks. We're getting there, it's just painful.

Fuel density wouldn't be such an impactful attribute if the US military and geopolitical situation and strategy were different.

Fuel density is logistically important and the US geographical position means that density is more important to the US than other nations. In other words, if we forecast that we'll be fighting foreign wars, fuel transport is an logistical problem that optimises for density.