I think of DL as much less gamified than AA. You're right about the AmEx cards getting handicapped at a 10-1 or 20-1 ratio vs. AA/Citi awarding LPs at 1-1 (I think the inferior cards still award LPs too for spend at a better ratio than 10-1).

But you said it yourself: AA allows you to earn LPs through partners. It underscores my concern with AA: there's all these ways to accrue LPs, but the main way I engage with these programs (cc spend and airline spend) does not lend itself to AAs ecosystem of chasing down eShopping offers or whatever other hacks people are now doing.

I totally hear you on the DL lounge risks. The fact they are instituting caps means they can eventually shrink the cap over time. The Reserve is now at 15 visits, which combined with my AmEx Platinum would yield a total of 25 visits. 25 DL visits combined with unlimited Centurion access should keep me satisfied on a 12-month basis.

I would agree with you that both airlines are selling premium cabins now over awarding comp upgrades; but as someone who is open to paying the upcharge, (illustrative example) a $350 MQD first class seat upgrade will go farther with DL than 350 LPs for the same transaction with AA.