Starting from first principles, this is my opinion for how $OP can be economically sustainable. My general philosophy is elegance, simplicity and minimal friction. No lockups, staking rewards and similar mechanisms - $OP will always be a frictionless, liquid token.
Assuming a MEVA/PBS-like setup, builders (sequencers) bid in ETH. Note: depending on the implementation, users may pay fees in other tokens (e.g. OP, DAI) to dapps/builders, but this is abstracted away from Optimism Collective.
ETH revenues are a) contributed to treasury and/or b) used to buy back and burn OP, or a combination thereof. Governance will decide the exact proportion, and dynamically adjusted in response to market conditions, governance plans etc.
There’ll be a dynamic issuance per revenues earned. For example, if OP is accruing significantly more value than the issuance rate, then issuance can be ramped up via governance vote. It could also be automated.
As always, governance (Token House + Citizens’ House) will direct issuance and treasury reserves. E.g. X% to RPGF, Y% to ecosystem etc. Staking rewards are possible, but in spirit of simplicity the buyback-and-burn directly accrues value to the OP token.
Post EIP-4844, both L1 fees & sequencer costs will be trivial (of course, no issuance required for safety, unlike L1s), and congestion fees/MEV can be very lucrative if we attract top developers and their users to Optimism. I believe $OP can be a rare economically sustainable token in the space.