I disagree a bit - for the first quoted paragraph, the last time I saw such a lucrative status match by major airlines, especially targeted towards elite of a single carrier, is so far back I can't recall when it was. There may never have been one as strong as Alaska's - all elite members of an airline FF program get matched to one level higher (if available) than what they have now, and they keep it for 15+ months simply by getting their co-brand CC.

DAL shareholders generally won't react unless/until they see signs it isn't working (e.g. depressed RASM relative to other airlines, reduced share of business travelers, lower margins, Amex reporting lower spend on DL co-brand cards, etc.). Right now it is all a guess as to whether this will cause issues, and the changes are phased in over the next 17 months so it may not be immediately apparent - based on when the changes were announced, The first sign of issues in the financial statements wouldn't even be apparent until January.