I've had conversations with junior devs that sound like this.

What core devs like Antoine don't seem to understand is that tolerating spam as a necessary evil, a floor willingly accepted to fund bitcoin mining and the security model, is a cultural shift in core development policy away from the harsh response that drove intolerable people like Vitalik Buterin away from bitcoin is that the development environment around the protocol was hostile to anything that he would wish to build upon it that is not for the proper function of a decentralised monetary network.

Spammers gonna spam, but if they build platforms for propagating industrial scale affinity scams a hostile development culture will always find innovative ways to cut their ankles off and force expensive adaptation, which has in general lead most of this unwanted activity to migrate to shitcoins.

It is clear to everyone in the community, including core developers, that the cultural shift is to accept and tolerate spam as a means to fund bitcoin mining once the block reward diminishes, until bitcoin becomes a medium of exchange sufficient to outbid this activity.

Everyone can see this strategy in play, and the way core developers nominally or verbally abdicate their responsibility towards the bitcoin policy layer, towards the determination of what is a monetary transaction and what is content distribution parasitically free-riding on a monetary network, while unilaterally forcing policy changes across the network by modifying defaults.

Spam is non-monetary transactions of any kind, and due to information theory it is punitive and self-terminating to attempt to control this undesirable behaviour at the level of formal consensus.

As a judge once said, "I cannot define porn, but I know it when I see it".

Spammers can harm the network, and taken out of context, the narrow quantifiable harm of embedding content in the witness or other more costly techniques, is not even remotely as harmful as a cohort of developers working on the reference implementation who make a deal with the devil, to save bitcoin from a threat of failure of the security model that is completely unproven, unjustified given that bitcoin must transition from store of value given the powerful opposition of the incumbent governance systems, and that an increase in the value of the token itself (store of value) is what prolongs the value of the block reward for sufficient time to reach the status of medium of exchange and increase transaction volume at L1. Blocks are not supposed to be full during the store of value phase.

The future may not pan out this way, but it's certainly not clear that a policy change is required to solve a problem (funding the mining industry) that is not clearly a problem.

Mining centralisation is a multi-faceted problem with many contributory solutions, it's not necessary to actively support spam in order to solve that problem. There are other things that can be done and are being suggested.