I definitely see your point, although a DEN-CUN codeshare wouldn't make much sense for AS and F9.
DEN-CUN passengers can go nonstop on F9. Why cut AS in on the fun when you don't have to?
Likewise, SEA-CUN passengers can have same-plane service on AS via LAX. Why connect them to F9 in DEN when you don't have to?
Codesharing to Mexico destinations on F9 via DEN would only make sense for QX, assuming they were to drastically increase operations there from places like GEG, BIL, BOI, etc. They are actually reducing their operations there, as the QX service to DEN hasn't taken off like it has for AS.
I know that at one point AS and F9 were discussing codeshare possibilities, but it just didn't make sense when all the options were laid out.
Here's my one reason for thinking a merger or buyout is a distinct possibility:
UA remains Alaska's biggest competitor, bar none. They've battled them for years, and have done reasonably well so far.
UA is Frontier's biggest competitor by a long shot. They've carved out a great niche for themselves in the DEN market, and have thrived there.
Now that UA is on the ropes...why not join forces to really take over the West Coast?
A combination of AS and F9, while not perfect on paper, makes for a West Coast juggernaut that can handle just about any threat and thrive in the most competitive air market in the world.
"In this present crisis, government is not the solution to our problem - government IS the problem." - Ronald Reagan
Comments made here are my own and are not intended to represent the official position of Alaska Air Group