Phone cameras didn't get worse when they went from 20 to 16 MP. You'll have more detail in a picture from a good 16 MP lens, than you'll have in a picture from a shitty 20 MP lens. And the fact is that before they started chilling with the MPs in phone cameras, all they used as a selling point was MP, which meant that that's the only feature they truly focused on, and the results were honestly shit.