Now that DL has announced their new status qualification requirements, the three major US airlines have distinctly different elite status qualification frameworks. This is quite an evolution from when they all had basically the same elite qualification systems with thresholds at 25k/50k/75k/100k miles.

I am no expert on AA and DL, but a little digging into the AA system and the new DL requirements leads to a few high-level observations:
1. AA: Massive status-earning value of credit cards. Massive advantage to retain status vs. earn status. Much harder to earn status the first time without significant credit card spend.
2. DL: Most similar to UA, but higher thresholds and more value (not as much as AA, but more than double UA) of credit card spend to gain status. Lounge access via all credit cards severely limited.
3. UA: Incentivizes spending on actual flying over general credit card spend for status than any of the big three. Credit card spend for status is relatively minor with lower earning and caps.

Clearly, credit card spend is very profitable for the airlines. My question is what drives credit card spend? Is it status qualification (AA>>DL>UA)? Is it lounge access (UA>>DL, haven't looked at AA)? Or RDM (where they are all presumably pretty similar)? If it is status, AA is all in on pushing credit card spend, and Delta is trying, but the limits to lounges will lead to many cancellations as well.

Probably because UA is the devil I know, and also because I prefer the majority of my spend to be on 2% cash back cards, I am very content with the UA MP system. I also like my unlimited lounge access with my Presidential Plus card.

Thoughts on all this and whether UA MP may evolve?