This is a good concern that some License holders will definitely feel.
I don't own any Licenses.... but in my opinion what makes the most sense is that SPS validators earn SPS as their reward for operating the validator network.
If the current pool for validator holders isn't sufficient to incentivize the validator network, the DAO could increase the Validator pool from SPS holdings instead of offering some other gameplay token unrelated to validators?
For example, @nateaguila has repeatedly said "glint is a reward specifically for participating in the ranked battles mode" which makes sense to me... as such I don't really think it fits my understanding to earn glint or DEC for running a node, but more SPS seems to make sense, assuming the DAO agrees....