"What will happen to the many government systems that will never get the chance to be AI-pentested?"

Oh, everybody's going to get AI-pentested whether they want to or know about it or not. It's the cost of being on the Internet. Probably the situation will continue to deteriorate. Both the British Library and Jaguar Land Rover recently suffered long outages due to compromises, for example. I suspect we'll probably just lose a few large, famous businesses entirely to compromises.

Businesses will buy insurance priced slightly lower than the cost of hiring sufficient security as to not need the insurance.

(Many already do).