I’m not sure in exactly what sense you mean, but I’d say it’s because it’s the same target demographic/business segment. No, really! I mean, all advertising is bullshit[0], after all. We want novelty but also familiarity. It validates our intuition and gives us the sense that we’ve noticed something someone else hasn’t even if that’s not true. If you pay close enough attention you start to see common denominators in branding, design, and yes, even copy like you’ve noted here. Our basic job as advertisers is to be aware of the landscape of these things, preserve and deliver the important elements, and successfully convey the client’s message. The standouts among us, whether by luck or virtue, deliver something just radical enough along the way. But I don’t think that bit is as important as some might think, if not in kind then, at least in degree.

Sorry if your question was mostly rhetorical or generally just tongue in cheek. I promise I don’t intend to patronize. I guess you inspired me.

[0]: https://en.m.wikipedia.org/wiki/On_Bullshit