In the scenario where leaseholders own shares in the freehold-owning management company, it’s entirely up to them whether they charge a ground rent.
As one thought, a ground rent in this case could be used to build a long-term sinking fund that could be used for any future major building repairs. I knew of one 1960s concrete apartment block where this was done to make provision for if/when major concrete repairs might be needed.
It’s something you perhaps should put to the vote of the management company members.