A company could make a pile of money from carbon capture technology, renewable energy, rebuilding flood-damaged areas, etc., too. The profits could even go to companies that currently benefit from the fossil fuel economy, which would mitigate a big conflict.

The issue I see is with problems that require politicians representing the people's interests to take the lead, not capital. The political organs of capitalist countries have become so subservient to capital that they're incapable of setting the agenda, even in ways that could easily be turned to benefit existing interests. So the public good, if it gets addressed at all, gets addressed a day late, a dollar short, and thoroughly half-assed. This is what we've seen with Covid, and it's what we've seen (to an even sloppier extent) with climate change, too. The collective action problems you describe are one species of this, but I think any crisis requiring decisive, immediate political action is a pretty bleak scenario under this advanced stage of capitalism.