Is it tragedy of the commons, then? Once things settle, won’t people learn that adding 1 additional GPU only increases my cost by 1 and doesn't increase my rew

Is it tragedy of the commons, then? Once things settle, won’t people learn that adding 1 additional GPU only increases my cost by 1 and doesn't increase my reward? Can’t we design a system where the number of transactions processed scales with the compute power of the system rather than striving to always keeping block time constant?