Isn’t regulation even less likely though than a split? You yourself acknowledge the times and the current admin is heavy anti-regulation.

Perhaps. You're right that it's currently unlikely, but I still argue that it would be easier to legislate than split up. It's not like the financial industry doesn't already have an insane amount of rules and regulations at both the state and federal level preventing them from being too nefarious. Having a rule that states "You're not allowed to cut off vendor foo just because they sell bar" doesn't seem that much of a stretch, especially if you look at credit as basically another form of legal tender.