I don’t understand. They want to spam. Spamming costs them money. They cannot sustain the spam because it’s costing them a lot of money. Am I wrong?
https://primal.net/e/note1ss06qph96theqe249qflx5kmg9pr4yhzegmn293eetlj7zt0dfeqdfsc5l
You are not getting incentive structure of the spam. They don't care about exchanging value. They care about gambling and speculation.
When purpose and incentives are totally different, you can't say that high fees will kill spam.
Discussion
What if one of these spammers are government entity. They can always print unlimited amount of money from their money printer and spamming the #bitcoin network for days (if not weeks).
It doesn't take much to do DOS attack on Bitcoin network with this legitimate bug.