Factories are staffed by people. Those people have the physical capability to change the way the factories operate. Any individual person attempting to modify / replace the factory equipment against their line manager's will would quickly find themselves out of a job, but collective action among factory workers (e.g. unions) might work. So might getting the line managers on board with the proposal, if you can get enough buy-in that "we used our discretion" is an acceptable answer: it's not like most companies actively want to pollute, rather that it's usually cheaper to do so, and they don't care about not. Being able to say "this move reduces turnover among our workers, slashing training costs; and you can probably use it in the B2B / B2C [delete as appropriate] marketing, since environmentalism sells in some markets; and this way, we're prepared for future legislation expected in jurisdictions A, B and C" may be sufficient justification. Alternatively, there may be ways to exploit the principal-agent problem.

I'm sure there are people who've specced out detailed proposals for this sort of thing. There might even be previous cases where they've succeeded, which we can learn from. Neither of those "two ways" you mentioned are things that I can do, but I may be able to slightly reduce the intensity of the opposition. (Companies tend to like when regulations require their competitors to do things they're already doing, after all.)

> Almost all emissions come from factories.

industry, transport and home use (heating & A/C mostly) are all roughly 30% of emissions.

(another way of splitting it says electricity, industry, heating, and transport are roughly almost 25% each. It depends whether you count electricity on its own or bundle it with how its used)

But I agree with you about solutions. The market will quickly bankrupt any companies that induce extra costs to decarbonify. It's the governments job to ensure that externalized costs like CO2 emissions are internalized via carbon taxes. (or alternatives to carbon taxes, which are worse)