Because the overwelming majority of consumer don't sit and obsess about bezels on a phone. Or differences in display color saturation, temperature, and comparative brightness...or the level of noise in that lower light photo, etc.
Don't get me wrong, I can appreciate what wonderful pieces of hardware the new Sammies are but typical consumers don't obsess about the minute details like the tiny niche of mobile tech enthusiast that post on forums like this do. Hell, most people are far more worried about what kind of case they're going to get---think they care about a few millimeters on a phone or that the whites on their display have a cooler temperature than another phone?
I don't get distracted by the bezels, but aesthetically they make a phone beautiful and modern, or meh and outdated looking. What does distract me is the much larger size, it distracts how it fits in my hand, how I can use it one handed, how it fits into my pocket, etc. That's a big deal to me and I appreciate Samsung continuing to evolve phablets by making non screen real estate less and less in order to increase functionality.
And I know I'll likely just be labeled an iPhone apologist but I don't ever recall using my iPhone and being so distracted from the actual content I'm viewing on the phone by the bezels that I just had to put it down and stop using it.
Let's be clear...most people's preferences in regards to their mobile device choices generally pertain to what OS they like to use. No mystery I prefer iOS and as great as the Samsung hardware is, it's not SO different from what I get from an iPhone that it's enough to get me to switch, because my greater issue is with the OS. Same goes for so many others here--they find Android to be a superior OS for their needs/preferences and even if the iPhone 7 all of a sudden leapfrogged over Samsung with its hardware implementation, they're not going running to the iPhone because they don't want to use iOS.