I was about to check Spamhaus's ROKSO list, as I recall it listed about 30 people on it who were/are collectively responsible for almost all email spam (but it'

I was about to check Spamhaus's ROKSO list, as I recall it listed about 30 people on it who were/are collectively responsible for almost all email spam (but it's down https://www.spamhaus.org/faqs/rokso/ https://www.spamhaus.org/faqs/rokso/). If malware is anything like that, the number of actors may be quite small.