Do you think people putting stupid monkey JPEGs on Bitcoin care how expensive it is? Or how difficult it is? Adding cost to the spam from people like that doesn’t matter. Cause they are creating the spam to either launder large sums of money or to sell their stupid shit to the next greater fool. The cost of the transaction doesn’t come into play for either situation. Op return limit could always be circumvented by direct to miner submission. Storing shit on Bitcoin is not economical at all anyway, so the belief that the lack of op return limit will make people use it for data storage seems unlikely. You can store data on an Amazon forever for hundreds of orders of magnitude less than Bitcoin, so if economics are driving spam the choice is clearly not Bitcoin.