Monopoly of DYDX liquid staking would of course benefit Stride, Reverie (as an investor), and the Stride validator set (may of whom have clearly indicated their COI here. Thumbs up for transparency.)
The question is less about what is good for Stride, and more about what is good for DYDX.
Is it good to subsidise just one LST provider, if the aim is to increase security and decentralisation?
Perhaps splitting community pool stake between two LST providers would offer greater security and decentralisation.
See forum proposal: Diversify potential dYdX Community Staking with Stride and pSTAKE Finance
pStake do not use a closed validator set, instead assigning stake algorithmically to increase decentralisation.
Financially, the DYDX community pool would benefit more by splitting the proposed 20M DYDX between Stride and pStake.
Instead of charging the reduced Stride fee of 7.5%, pStake propose charging 0% fees. Additionally sharing 20% of their entire DYDX liquid staking revenue with the DYDX community pool.