So I checked how much it cost to upload a picture of the tweet by Luke Dashjr talking about a spam filter, and it was .0001617btc. That's, based on yesterday when I checked prices, usd$3.24. That's super cheap. The "witness" data is at a 75% discount. I know 1 sat/byte won't always go through, but that might often be the case, at least during the next couple of bear markets.

Normally I'm a "it's not spam if you pay the fee" but uploading a picture to tens of thousands of computers for under 4$? That's a loophole, not really paying the fee. 20$ would be paying the fee. Even during the last "bull market" the mempool kept clearing. I think people who are "it's not spam if you pay the fee" types would feel better about the situation if it meant a robust security budget.

There is also an attack vector that I don't even want to say out loud here, so I won't.