It's an interesting argument. The fact this article exists is somewhat proof that it is a differentiator. The flipside, however, is that spammers very specifically require their emails to get to add many mailboxes as possible, so their motivation is greater to make their emails service compatible.

Company sys admins have likely got all sorts of other issues to worry about, and the occasional report of an email not getting through is likely low on their to-investigate list.

Having said that, I self host a mail server, and have all those things setup correctly, and my workplace uses Outlook, and I've not had issues with delivery, so it's not a particularly difficult bar to jump.