What about the bots?
M3AAWG published a letter to the FCC addressing the implementation of CSRIC III Cybersecurity Best Practices (pdf link)
The takeaway is that of the ISPs that contribute data to M3AAWG (37M+ users), over 99% of infected users receive notification that they are infected.
I hear from senders occasionally that they are not the problem, bots are the problem and why isn’t anyone addressing bots. The answer is that people are addressing the bot problem.