I get >50% of my spam from legitimate hosts such as gmail and yahoo, which tick all the spf/dkim/dmark boxes. spf/dkim/dmark helps with phishing/forgery, it do

I get >50% of my spam from legitimate hosts such as gmail and yahoo, which tick all the spf/dkim/dmark boxes. spf/dkim/dmark helps with phishing/forgery, it does little to nothing for spam, even though this policy change makes it look like it's connected. If I send spam through gmail, the spam is "authenticated". spammers were among the first to implement these in an attempt to get higher score in spam filters. For quite a while dkim was positively correlated with spammyness for me. Meanwhile.. does google even respond postmaster@ or abuse@ requests?