True, and I agree some products are a bit better than others, and some will have different characteristics during application, but the end result is more or less the same in many cases. I could probably wax my car with off the shelf liquid Meguiar's and tell you it was 50/50 wax on top of sealant and glaze etc. and my guess is nobody could tell the difference.
My comment was more for people who, say, buy the 3-4 polishes in the Wolfgang line, then the Adam's line, then the Poorboy's line, then the Menzerna line, then the Optimum line, etc...at the end of the day they've got 20 bottles of polish that really aren't much different. I dunno, that's just something I read from a professional who's been doing it 20 years and said he's got bottles and bottles of stuff like that that he's either never used, or barely used, and all it got him was an empty wallet.
Of course we all like detailing, and it's another money pit, and that's why we are all here, myself included.