Selfhosted

What registrar was that? Were they as big as Cloudflare? How exactly did they "go tits up"? Isn't the situation you describe a completely different scope from an individual's usecase? It's also an anecdotal point of data without including the full context of how common that situation is. "It happened to me once, and I have heard stories" does not necessarily mean it's common enough for everyone to prepare for every time. I'll remain skeptical of the

Mainly, though, I'm not saying it's a bad idea in total. I just think that for someone who is inexperienced with DNS management and self-hosting, those types of concerns are already unlikely and just keeping the environment simple and cost less has far more value than being prepared for unlikely scenarios. It could even prevent self-inflicted issues by keeping it simple, which would be far more likely than Cloudflare's infrastructure creating a problem that they have to remediate themselves.

If anything, the true argument for risk mitigation would be to have multiple DNS servers for redundancy.

I just don't believe that, in this type of usecase, it's worth pressing for and that there's more of an argument to keep it simple.

Additionally, you can leave out trying to use your credentials and a hypothetical group of people to make your argument for you. It makes it seem like you're trying to talk down.