While I understand what they're getting at here, I disagree. There are certainly other providers you can go with - You just need to pay up.
Happy customer of FastMail here. All of my personal domains, and multiples businesses are tied to it. Wonderful service, no deliverability issues, great features, etc.
So - clearly other companies are able to get it right. Self-hosting is probably difficult, but it's not like you're forced to go to Big Tech.