Google/Microsoft didn't kill email, spam did. Google/Microsoft then salvaged from the abyss something largely similar to email, but with some limbs all but severed.
Spam put centralised commercial e-mail ( ISPs and web-mail ) into critical condition until the web-mail hosts reacted to save themselves.
But as for the little folk who are less of a target: I have run my own mail server for 18 years and can't imagine I've received more than 100 spams in total. And that is without any defences other than SPF.
ISP e-mail, well that is certainly spammed to death but probably for the best as it was only ever a hook to keep people trapped in sub-par services.
I also run my own email server, and I've received 400+ spam emails this year alone, just from the eBay leak of 2014 :) Thankfully I use a different address for each service, so I blackholed that to the spam folder and created a new one.
I have a personal domain on Gmail, and my spam folder currently has 105 messages in it from the past month. Two are mis-filed mass mailings and one is from a mailing list that I think I was once legitimately on, but which has refused to unsubscribe me. The rest are from russian women who thinks I'm sexy and a few from the Nigerian central bank (that's apparently still a thing, who'd have thought).
These are the emails that are not related to me being on a centralised commercial host, and they all made it past Googles ample defences.
That tells nor about the state of alleged defenders than state of email. 2009 vintage spam filter (CRM114, OSBF, extra weight on headers) is easily much more accurate in all senses than GMail alleged spam filter. The problem with GMail is it uses some generic idea of unwanted mail that never correctly applied to the mail you receive in the first place - to save space on personalised filters and speed up processing. Oh, and to extract global statistics.
