You can look through my history how many times I’ve brought this up to people and they just don’t seem to care. A defence is that they’ll buy the domain for a century and not care once they’re dead which is fair but the situation in this article is a valid one. I will always stick with Big Email for accounts.
I moved to a third-level .name domain in 2005 precisely because one of the Big Email providers (Google) locked me out of my account with no recourse; presumably because I had a very common email address that was getting a large number of login attempts from other people which had triggered some abuse automation.
At the time - before the explosion of new gLTDs - third-level .name domains were advertised as the 'correct' domain to register for individuals wanting personal email addresses.
Your response seems to imply those people are irrational, but it's really just different priorities. Yeah, you need to make sure you don't lose the domain. With Google/etc, you need to make sure you don't break any of their usage policies across their suite of apps, etc. Neither are super likely to happen. Neither are impossible, either.
(Update: as it happens… https://news.ycombinator.com/item?id=49548452)
Personally I like having a custom domain as I like the idea of being able to move between providers. So far, over the past decade, I've hosted my email with Google, Fastmail, Hey.com and then Fastmail again. I like being able to move it around if I find one provider better than another. Others won't care, that's fine too.