I was just going to say something like this.
More players causes demand for cards, SPS, and DEC to go up.
Causes the DEC rewards pool to go down per player. May also dilute the SPS airdrop pool per player (though this effect would be minor with new players I'd say).
Other ideas:
Increasing staked SPS in total causes a stationary amount of Staked SPS to produce less vouchers.