No, separating branding and separating management are substantively different ideas, not a matter of semantics.

> All major corporations have highly speculative projects that they aren't certain will succeed. With (relatively) minor investments most don't form an umbrella corporation to distinguish them.

That doesn't support your argument that it's a semantic distinction, it instead seems to be an unrelated argument with some implicit premises that argues that most corporations wouldn't have done what Google did to separate Alphabet in similar circumstances, which may or may not be true but is irrelevant to what the point was of Google doing it.