What I don't understand is how CX seems to make it work with crew bases at every outstation they serve. (And yes, I know CX are on their own BA-inspired cost cutting path as well, but mostly that's due to their suspicious fuel hedging activities, not because they're actually losing money).

Really from the outside it looks like BA's playbook is to eventually outsource every employee, and then replace the outsourced employees with automation. At some point there won't be much of a need to have a management team because there won't be much to manage, at which point all of IAG can just be run by AI and software. Of course if every company follows this path, then there won't be much of a business left to fly people around, as no one will have the money to actually fly anywhere!