Hi Matthew, to answer your question:

(Assuming core has not been corrupted), these are a few possible motivations of what core might be thinking:

1) “changing things at consensus level to stop spammers is a pain in the ass for several reasons (reaching consensus, code maintenance), so let’s first try this method and let’s see if it works”

2) “the best defence is to be as open as possible: if we try to stop spams with filters or at consensus level, they’ll always find a way in eventually. Let’s instead open it up completely and hopefully the market will sort it out for good”__(personally I wouldn’t mind this approach, just afraid that perhaps btc is still in the nurturing phase and still needs some “monetary focus” protection before being strong enough to be open up completely ?)

3) “we have a mining centralization problem, since we don’t want to stop spams at consensus level (see point #1 above) this is the best we can do to prevent further centralization at the moment

4) btc is fundamentally based on game theory, let’s actually let it play out and see if the players want more a “money database” or a “spam database”

FYI, if it was for me I’d change things at consensus level cause I’m a “monetary maxis”, but I am also not adverse to other use cases as long as they don’t greatly impact/prevent the monetary aspect of btc

Ciao