since when does popularity make something the best? In many cases it's often the opposite. I'd insert a US Political comment but the mods would frown I'm sure
----------
actually most consumers are stupid. the most popular and well sold products aren't often the best, just the most popular.
Which then begs the question of what being "the best" entails.
Take Justin Beiber or Taylor Swift or one of those "dime a dozen" K-pop girl groups for example. Their popularity is undeniable. You can argue about how they can't sing compared to whichever standard you want to hold them up to (I dunno - who's considered a good singer these days?).
My answer then is - so? You are assuming that people choose to follow an artiste based solely on singing prowess alone, when in fact, it's really the whole package deal, including other factors like accessibility, age group, sex appeal etc. Different fans have different criteria as to what makes an artiste entertaining, and that's really what matters. Whether that performer is entertaining to me or not.
Same for smartphones, or any other device. I don't know what metric you are using to determine what the best smartphone in the world is, but I can tell you that it is not as significant as you are making it out to be. Simply put, different people look for different things in a product. Some selling points are more relevant than others. Not every spec which can be quantified matters, just as not every factor which matters can be quantified on a spec sheet.
I like to believe that most (if not all) consumers are rational. The problem here is that you are artificially limiting the definition of "rationality" solely to factors which can be readily quantified. We need to move beyond these parameters if any such discussion is to be a meaningful one, IMO.