Most of the vegetables you find in supermarket nowadays (since the 70's I guess) are from new type of seeds designed for mass production and profits. It's usually fast growth super regular vegetables. In the end you have good-looking vegetables, big and regular size, with bright colours, no stain or whatever and they all look the same in the rack. But inside it's just tasteless water because it grew too fast. We find more and more of these in European supermarkets (and even local markets) but people are well aware about it and only uneducated people buy them. And here in US I only find this type of F1 hybrid calibrated vegetables.
PS: I've been there for only a few days so it's just my personal experience, not a well documented/studied thing, that's why I ask for advice