I have no idea why that was the case and can't even speculate since I don't know enough about how the networks worked, but I would love to hear an explanation. I was pretty annoyed by the fact that I still needed to own what I considered a phablet, which was sitting collecting dust on my bedside table at home just so I could have the type of phone I really wanted. Seemed like a punishment-by-design for trying to step off the typical customer rails.
My tastes have changed slightly these days, and I'm okay with a 5.X" screen or whatever, but now I want it to be eInk or something similar and focus more on text/sms as I've gotten pretty minimalism with my phone use.