Without a legal way to make payments, companies can no longer justify the tradeoff of paying up and fixing the leaks as they spring up. This incentivize them to give importance to security and actually overhauling their infrastructure properly.
If everybody agrees not to pay ransom and follows through, criminals won't try to hack companies to collect ransom.
But as an individual company, you can't coordinate with everybody else to prevent everybody from paying ransom, so not doing so puts you on disadvantage.
Philosophically, the usefulnes of government is to threaten violence to solve the coordination problems amongst individuals.
People rarely understand that the coordination solution is one of the most important powers the government offers over privatization.
They can tax/penalize undesired behavior. Individual companies may end up worse off, but as a whole the business community is better off with the rules in place.
This is why governments have to tackle pollution and climate change too. Companies are profit-motivated, and will only respond to what the economics demand. When governments start imposing demands with penalties attached, that's when companies actually start changing behaviors.