The organisations buying up land have more members therefore more cash to spend than the shooting organisations
It has worked for some of the wild fowling clubs, but its a different thing, they limit shooting to the members and a few permit days for others, would be difficult to organise in say a stalking type purchase, or even more difficult in game shooting.
But cost being the biggest problem, would you be prepared to pay an annual membership of £500 to £1000 to
an organisation and even then have to enter a draw as to when or if you could shoot on the ground, don't think that many would prepared to pay that sort of money to an organisation, plenty complain about costs at the moment.
Its not a bad idea, but its not practical, the cost involved are horrendous, just think of how big a purchase would need to be made for members to be able to shoot when the want impossible! OK smaller areas then its a lottery system of who and when you get to shoot, and when you look at how much they would have to increase membership fees to cover the purchase cost, and don't forget you have running costs after you have bought it
You only need to look at estates, to see how hard it is to make land pay.
When you take everything into consideration IMO its a non starter.