If it's going to be cheaper, why does it need government support? Won't industry just do it to be more competitive on its own? Or perhaps there's some kind of first mover/network effect/chicken and egg problem that the free market can't surmount on its own?

Most things have government support, cars have roads, oil has militaries, and everyone who pollutes gets to do it for almost free with government support of not making it illegal.

But mostly it's long term vs short term.

I'd just make pollution illegal unless you paid to clean it up

> drastic action which tanks its economy

None of what you proposed can be reasonably considered drastic action, so you're not really in disagreement with OP there.