Not really sure what you mean by misnomer or what an “actual public cloud” would mean. It’s called public cloud to distinguish it from private clouds which plenty of large organizations have. The big cloud providers license their clouds for such deployments. Unless you mean that a “public cloud” should mean something like non-corporate governance?

With things like kubernetes, it’s easier than ever to deploy your own private clouds these days.

I think the only misnomer is the word “cloud” itself. We had the term “hosting providers/companies” which is exactly what these public cloud are. It’s just that the term “hosting provider/company” had about 15 years of precedence that almost always meant “small scale hosting”, so they just came up with a new marketing terms