I don't think that's true. The spam filters do incentivize things like Slipstream, yes, but Slipstream has a bit of an issue: it is always risking that in a race condition, it could lose, and most likely would lose, all of that work. We could exploit this race condition to make it even more penalizing to miners, perhaps, when they do not respect what the network is telling them. Greater miner decentralization via OCEAN helps, and miners make better margins on OCEAN so there is a strong incentive to use it for any educated miner out there.