I'm not sure we're living in the same US. The USA I live in is one of the few countries not agreeing to climate change, with a subset of its population not even believing it is real.
I'm glad you are doing policy work - it is important. But I'm not ready to declare the problem solved in our own backyards quite yet.
One economic model suggests that "if a carbon tax imposes a dollar of cost on the economy, induced innovation will end up reducing that cost to around 70 cents".[72] Given that political acceptability is mainly a function of cost, making clean energy cheaper might make carbon taxes more likely.
The current US administration was considering significant cuts to its energy R&D budget and has not advanced Mission Innovation.
But recently it appears as if a unique window of opportunity has opened up for policy research on the effectiveness of higher and smarter clean energy R&D spending. The Mission Innovation secretariat is now led by the EU and Canada. And it also now appears as if there will be a slight increase to the US energy R&D budget. It might increase further in 2020, because there is a chance of a change in US leadership after the 2020 elections, which might affect clean energy policy.
citations here: https://lets-fund.org/clean-energy/
Are you mixing in nuclear with coal and oil and calling it a fossil fuel?
Besides, the efficiency of fossil fuels isn't the issue. Their impact on humanity and the planet is the problem we're trying to solve.
Freeman Dyson pointed out that in engineering, unlike science, competing ways of approaching a problem rarely coexist. The better (including economically better) solutions drive the others to extinction.
Nuclear right now is on the losing end of this competition. Levelized cost of power from new nuclear power plants is not competitive, and it's not competitive by a wide margin. Nuclear is dead tech walking and, absent some a near-miracle that changes this, will go the way of the zeppelin, the reciprocating steam engine, and the vacuum tube. It could persist in niche markets, but for general use it will be dead.
Sun and wind need backup systems either coal, oil or nuclear once you factor those in and factor in that coal will be more expensive because it only has to run as a backup then you realize that wind and solar is not even close to being relevant. That's not factored in.
Sun and wind currently is about 1% of the entire energy market projected to be 4% in 2040.
New nuclear is grotesquely uneconomical, and unless a cost miracle happens it's dead technology walking.
Do you realize that technically, this sentence doesn't make sense ?