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The spammer increasing their fees just causes legitimate transaction fees to increase since wallets use dynamic fee calculators, this prices the spammer out of the blocks since transaction fees are relatively small for the legitimate users but large for the spammer(since they are trying to buy a lot of block space). Without a cap fees would likely be too low to price the spammer out of the blocks.
The point of the spam is not to buy blockspace since there is way too much spam for that, or even compete with the ham but only to spam the nodes. Fee filters are not a defense since the spammer sets her fees above the filter but below the ham.
if bitcoin core developers will resist to increase block size, we can say good bye to bitcoin.
as without confirmations it is nothing more than rubbish