Yeah, I assume many will not use it all, as Azir said, a lot will lay vacant. Unfortunately, no squatters rights :D
If summoners get so short in supply, can you imagine the value, both selling and renting? It might be more profitable to do this than harvest the land
Exactly. So for those who don't have land, they might be in for decent profits too, but I assume that if those with Land chase the rent profit, the profits for those remaining on the land will increase also. With the right balance, it would be a pretty interesting economy.