ASM additions from long-thin routes like SFO-CTU notwithstanding, the overall trend in UA flying has been significantly downward. One would assume, perhaps improperly, that there's a method to the madness, and there's a "right size" that UA is headed for?
The 'right size' UA is headed for is smaller than UA now, and will end up being around 3rd place overall.
When they began this round of consolidation, CO was #4. (after AA, UA, and DL in that order), overall. They're now 4th domestically (WN).
I don't think its inconceivable that VX and B6 wouldn't form some sort of partnership, and become a significant pain in the butt for the majors, particularly UA, slurping up the most heavily trafficked domestic corridors (BOS/NYC-> West Coast, ORD and Florida), where people want and expect a modern, high quality product.