Education is now free in Scotland. That means it can be done. That means people can make it be on offer - as NUS Scotland did. However, this is helped by the fact that England subsidises Scotland through the Barnett formula. (Not something I am against as such, but I object to the SNP taking the credit for things England is effectively paying for.)
It is also free in a raft of European states - Denmark, Holland, Sweden come to mind. Probably more.
I believe continental Europe also generally charges higher taxes across the board - probably more than you'd ever pay under student loan repayments.
This isn't to say that free education at 50% participation can't be done - just that you may be unpleasantly surprised by the things that would make it possible.
