If they aren't profitable when taking into account their negative externalities than the owners are stealing from the rest of the world and they should go bankrupt. They'd probably figure out a better way to do business instead though

The incoming government in America loves the idea of tariffs; why not frame it as part of a trade war in a theoretical government set on ending climate change? Place heavy tariffs on any goods that do not have the same cleanup obligations.

I don't understand why enacting a 20% tariff on all imports makes sense, but enacting a 20% carbon tax on every company in order to pay off the damage of pollution is literally unthinkable and would cause every company to go under.

The days of letting companies do whatever the fuck they want and doing nothing to steer their incentives in the right direction are gone. It doesn't work, end of. We need to nudge them to do the right thing, and the only thing humans care about is money.

tariffs are there to give Western oligarchs an extra stipend in the form of more competitive pricing without the work. a carbon tax would punish Western oligarchs along with eastern ones, and therefore not acceptable.

Honestly I doubt it, because these Western oligarchs rely on cheaper labor and manufacturing in Eastern countries. I don't think any domestic companies will be able to compete even with the tariffs.