You might be wrong there. I'm wondering where you get you data from that most have 4k TV now. We are talking about international console launch here with millions spend on gathering data. I doubt Microsoft get the data that suggest MOST already have 4K tv yet decide to launch a console only capable for 1440p.
Even 2 of the panelist for IGN weekly postcast don't have 4K tv and are gaming at 1080. My point is though a PlayStation owner all the way here, I feel that xbox have done something really right and interesting for this launch. Targeting both end of the low and high end player.