I think there will be a number of changes.
The top selective schools will stop offering bursaries to anyone who isn't also one of the strongest scholarship candidate. (Starting to happen now).
Some schools will switch to catering to those with very deep pockets but whose children are not academic superstars and provide amazing facilities.
Parents who aspire to private education will have one child (already seeing this - the vast majority of our friends who are/are thinking of private education have only had one).
Those who are priced out will switch focus to selective and top state options.
What will disappear are the smaller schools that offer small classes, fewer frills and provide a non state alternative for those who can't afford the big name schools or who don't have kids capable of landing the scholarship bursaries.
The latter becomes an issue when areas of the country can't attract GPs because they don't have good schools, or when parents have children with the kind of SEN that struggles in a standard comprehensive but aren't in need of special schools.
All of it leads to less choice and more elitism - whether that is academic or financial, and enhanced competition within the state sector. It also doesn't help the countries birthrate which is not a good thing for growth or prosperity. None of it provides extra resources for the state sector, and the people that will suffer most will be those children who don't have parents who are making their education a major priority.