Earlier quoted context omitted.
If you're really curious setup DMARC as well and check out the reports. I used to work for a company that did DMARC analytics, and after setting it up for my personal domain it's kind of interesting to see who's trying to impersonate you (or who's getting spam purportedly from you).
None of the big providers send DMARC messages. Google doesn't. Microsoft doesn't. The only DMARC messages I've ever gotten were from Yahoo and mail.ru. Google/Microsoft don't send DMARC reports because it would make it easier for spammers to know they had gotten past those filters. It's easier to just drop everything they don't like silently. It's why e-mail is terribly unreliable today (much more reliable if you DO…
Is that a recent thing? I was getting DMARC reports from both Google and Yahoo as late as April this year. Around then I pared down my Sonic account and they ate a bunch of stuff that I was too lazy to setup again including DMARC. While Google and Yahoo make up most of the reports I got this year, I also see some from Microsoft and AOL from 2017. 163 (China) used to send out reports too.