Eliminate them as a class!
The solution to this problem is relatively straightforward. A lifetime contribution limit should be introduced. The sum could be discussed, but when £100,000 represents significant savings within the UK at present a cap at this limit would seem appropriate and could be applied from now on, preventing anyone with this sum in ISA accounts from making further contributions in the future.
Can’t allow anyone to become financially independent now, can we? If we did then how could government retain power over them?