In principle the insurance company then dictates security requirements back to the company in order to keep the premiums manageable.
However, in practice the insurance company has no deep understanding of the company and so the security requirements are blunt and ineffective at preventing breaches. They are very effective at covering the asses of the decision makers though... "we tried: look we implemented all these policies and bought this security software and installed it on our machines! Nobody could possibly have prevented such an advanced attack that bypassed all these precautions!"
Another problem is that often the IT at large enterprises is functionally incompetent. Even when the individual people are smart and incentivised (which is no guarantee) the entire department is steeped in legacy ways of doing things and caught between petty power struggles of executives. You can't fix that with financial incentives because most of these companies would go bankrupt before figuring out how to change.
I don't see things improving unless someone spoon-feeds these companies solutions to these problems in a low risk (ie. nobody's going to get fired over implementing them) way.