Some things to consider here are that the claiming of lands is by far the easier part and we hope to have that live by the end of this year or early next year at the latest at this point (it is being actively worked on right now).
Whereas the next phase where land can be used to harvest resources and build buildings and all of that - which is where players would be able to earn SPS through working on land - will probably still be a bit further off.
So our thinking was that SPS rewards would be given out to land holders until they could start earning SPS through actually using the land in the game. That's why it is written in this way in the proposal.
If enough stakeholders want that changed here then we can change it, but I don't think I've heard that request from anyone else thus far. Additionally, keep in mind that when land is claimable, if the community feels like the SPS rewards should stop, they can always propose and vote for it at that time (or any other time). Nothing here is set in stone.
If a date for SPS airdrops to stop is set in stone it would give speculators a trading opportunity. What we want to incentivize is long term holders.
I am voting yes in its current form with no changes.