I think you missed the key reference to the "first several rows" part of that. So really this sounds pretty much like the front part of the economy cabin is handled on AC for its elites, in theory. If you're on a TANGO fare you pay for your seat, so in effect we elites are paying for our choice of a window or aisle when flying on T+ or LATITUDE fares. And like E+, why not offer a benefit exclusively to your own elites. Particularly in a NAmerican context where those members could defect/or already have defected to UA or AC FF programs.

I was booking my flights on US the other night and actually selected aisles and windows in rows 7 and 8 on most flights except the 733 which seemed pretty "full" in the first rows before the emergency exit, so I opted for a row or two behind that one. The rest of the plane was pretty empty, so I find there is a tendency for those who pre-book seats to go after ones in the first few rows of coach.

As noted, US's fares are generally the lowest on most routes even a few days before flights, unless they're sold out. I was looking at visiting friends in both Kentucky and Oregon this summer. Pricing the best AC/UA fare to PDX from YYZ came in at $650 or so. For the same price I was able to book US down to Louisville to visit those friends, then hop on UA to PDX and back. (UA fare was half ex-Louisville as it was ex-YYZ, thus paying for the US flight/Kentucky trip.)