With those thresholds, it's a good incentive for people who are going to be paying for a lot of additional international J flights to keep flying DL (operated or marketed), but unfortunately this doesn't really encourage additional Amex spend for most people
I would argue that for the majority of DMs, these thresholds likely do nothing to incentivize more DL flying (let alone CC spend). I expected DLs targets to be higher than UA/AA (what else is new - gotta pay for that "premium" after all), but I find these figures laughable. An incremental 7-10k I could see, and I would pursue that for extra GUC, but not +22k beyond regular DM level. Also, someone who spends 100k+ on DL tickets is unlikely to be motivated by the relative crumbs that are CB.