ffI

But that was the only reason for some high spenders on cards to fly DL

The program is a joke now.
I speak as one who has flown on SQ F on DL miles 70k each way to Singapore in the distant past.

DL Miles is the worst program and that does not change
AA and UA miles have more inherent value and I spend on AA and UA cards as a result.
The DL spend was to keep some status, which will not change, for <PM, but why even keep that going?

1
DL miles from flying were devalued by increasing the amount required for awards and the fees. They almost equal BA flying out of London.
2
DL miles from Amex transfer were also devalued by above
3
DL miles from Amex cards had some value for the incremental and incidental benefit

This move chips away at that incidental benefit of the cards
I gave away my DR MQMs from spend. Now I will close the DR and keep the SPG for spend and Plat Amex for all my paid airfare trips

4
If I was stupid enough to be loyal to DL alone,
AND
If I had enough money to spend I can hit 220k spend for 100k MQMs and get 30 more from a family or friend spending 60k, but what would that get me?

Nothing that spending a few 100$ on any airline flight alone just to sit in F would not get me. DL has destroyed loyalty as we know it, not only to DL, but also to the bank supporting DL (Amex)