You make good points. And yeah, I still refer to it as the CS100/300 and I have to correct myself when I type that. With all of this said, however you look at it, JB and Allegiant both have massive A319/20 fleets that are 4-5 times larger than VX's bus fleet was at merger. I don't see AS management having the appetite to take on hundreds of A319's and A320's after their history with VX's significantly smaller number of buses, so I do see a large, (mostly) airbus fleet as a deterrent to them either way.

I don't know if AS bid on the original Amazon Air contract. I am guessing AS wasn't willing to go low enough for what Amazon wanted; but knowing AS management, I think they certainly would see a business relationship with cross town Amazon as a benefit, in addition to the universal benefits of diversifying your flying more in the event we are headed for more pandemic and/or economic turbulence in the coming years. SY currently has a dozen NG freighters flying for Amazon and business is booming like never before for both Amazon and freight in general. I think if AS buys SY, it's not too difficult to see some compromises made that would be mutually beneficial to both AS and Amazon to keep and even expand this flying. Would AS chase this merger just for the Amazon flying? No, I agree, that's ridiculous. But is the prospect of getting this Amazon flying a mouth watering proposition to Angle Lake on top of the extra airframes and the M&A to stay relevant bit? Seems possible to me.

Of course, anything could happen. Now that Allegiant is getting Boeings, doesn't seem unreasonable to think they might also want SY. I never thought SW would buy Air Tran and they did, so they might also go for SY and they might be able to justify that more easily than a M&A with AS or G4 given how small SY is. Who knows, but as the smallest mainline carrier in the remaining group, I definitely see an SY merger with someone as more likely than just about any other remaining non-Big 4.