1. You don’t understand incentives. Not mining low cost transactions has nothing to do with mining higher fee “spam”. 2. Datum won’t solve for miners who specifically choose to mine spam because they want to make more money. All datum does is make sure miners have better control over what they include in their blocks regardless of what the pool would want. A pool of miners who want to mine garbage for the money will outcompete all other miners. Your solution just accelerates the issue.