I have posted before that I think 5/24 is a disservice to cobrand partners, and that's going to come to a head at some point when partners start asking why their cards aren't performing as well as competitors' cards.
I have never been involved in credit card partnerships or cobrand discussions, but having been in a lot of different types of corporate discussions and partnerships, my guess is that there were no discussions to speak of between Chase and their cobrands about 5/24. Though I know some people here think with that many big brains involved, every detail is analyzed carefully, I can say that is not the case with some different but parallel things at big companies (names you've heard of). Sometimes it's on line 237 on a document somewhere or maybe it's on a document that is referred to by the document you see and you'd need to request that document to be aware of the issue. Maybe you hear it mentioned in passing but don't realize that it's unusual for Chase or that it's an obstacle.
I don't think it's a huge deal, since 5/24 won't affect most people with good credit anyway, but I do think they are losing their cobrands a little market share and revenue. I can say personally, I won't fly United or Southwest until 2022 because of 5/24 and I am someone who pays annual fees for airline cards and buys tickets on airlines. I may not represent that many people but I know I represent 1 person and I am guessing it's more than 1.
Getting more extreme on this would be that much more of a disservice to partners. For core cards, Chase can do what it wants. Why they think this is a good idea but Amex and Citi don't think it's a good idea is a question for Chase, I can imagine reasons, and it's their business anyway. But as for cobrands: Amazon wants cards in people's wallets so they shop at Amazon and not Target or Walmart. United wants cards in people's wallets so they fly United instead of Delta or American. Etc, it's just a different dynamic for cobrands, where the card is more a marketing tool than it is about making money on swipe fees, interest, annual fees.
For anybody wondering why I keep posting about this ... it's something very visible to me since it blocks me from getting Chase cards, but to be honest, there are no Chase cards I'm dying to have. I just think this is an obvious unforced error, and I bring it up so that Chase and their partners may see it if they go online to see what people think about their cards. I'm not particularly trying to persuade MyFICO forum members.
Just a rumor! I can't see 2/24 happening unless they want to kill off their co-branded travel partners in a time of need! 
2/24 is way too extreme, especially on co-branded cards, but Chase has access to data that we will never know about. If this is true, we may see Citi, Amex, and even Cap One following suit in a way. Chase is #1 in assets in the USA, and that money isn't mostly from playing the credit card game. Citi being the #1 card issuer in the USA has more to lose when it comes to restricting cards to certain profiles as their card portfolios are more of it's bread & butter.
Chase was the first to predict a recession this time around, so they might be trying to head off bigger losses at the cost of growing their card portfolios for the time being. If 2/24 does come true, it's certainly not sustainable in the long run. So far, I haven't heard of Chase CLD'ing people for carrying a minimal balance (I'm carrying about 15-20% on my Chase cards for the time being.), and I've read that Chase has boosted the amount of cash that it has set aside for bad debt/charge offs in the future. Limiting risk during these times does make sense as I'm sure there are people right now willing to sacrifice their credit profile to make ends meet and no lender wants to be a part of that.
