As @Prolix has pointed out, under current legislation it is nigh on an impossibility.
The Government could enact new laws governing football clubs, but if achieving a 50%+1 fan shareholding is an objective (at a price substantially less than market value) it would require the adoption of policies more closely aligned to The Communist Manifesto than that of the Tories.
That ownership structure is not unconstitutional; compelling private owners to arrive at that structure would be.
Germany didn’t have to force anyone to sell off their ownership of a football club because they were set up from the beginning to be collectively-owned.
My accounting/finance has always been rather rusty. I’m not stretching the discussion or even exploring options, but just for what if’s sake; how about IPO?
FSG floats 34826 new shares which the fans buy. There’s a majority stake of the fans and the money goes into equity fund.
Yup, the only possibility in order to get out of the current system would probably be to declare football clubs non-profit organisations. But it’s difficult to envisage any government going that far as long as there is so much money to be made from that sport.
As Prolix said, it would need the total implosion of the current system to be able to envisage something else.