I get the point the author is making re: LARPing, but this kind of attitude and tone is bordering (or, bluntly: is) condescending to anyone who doesn't know as much as you. It's a huge shame because the general discussions surrounding privacy/security are absolutely rampant with paranoid bullshit, and stuff like this just doesn't help. The people you consider to be LARPing might honestly just be new to the idea of security/privacy/encryption/(insert your label here) and would be better served by a tone where you're not talking down to them, especially if you're an established authority.
Personally speaking, I use encrypted email for my personal account - but I'm under no big illusions about it, and at this point it's partly out of laziness as I find moving email providers to be a useless exercise in wasting time. My original use case was my wife and I wanting to send documents back and forth easily, have it encrypted and retained somewhere that's (relatively) easily searchable, and isn't one of the bigger email services. Email is a workflow that goes back decades, and I'm not particularly interested in changing that mental mapping in my brain (a feeling I suspect many would echo).
It's email. It's not encrypted or 100% private if I email my buddy who's using Gmail/etc. It does jack all for my bills, newsletters, and so on. I'm not worried about the metadata not being encrypted because if I needed that level of security, I'd use Signal or some other tool.
You're probably right that it can't be "fixed", but there's also nothing wrong with attempting marginal improvements until an eventual replacement comes along. It remains a convenient "it just fucking works" and until something replaces that, and interoperates with the rest of the way the world actually works, it's probably not changing.
My 2c, at least.