The question I have is why are you trying to rationalise this? As BA is disincentivising you to fly with them, then just go and move your spend elsewhere, and no longer deal with BA. In which case the success or failure of BA is of no consequence to you. Unless you are a large shareholder of IAG of course, in which case it would be fair to question the business merit of this decision. Otherwise you are just wasting energy trying to find reason in something, that you do not have the data to make any good conclusion about.

This is no different to when companies lay off employees, or if your client cancels their contract with you. You cannot take it personally, and you cannot spend all your energy trying to understand the why. You can of course trying to provide feedback, or ask for insight. However no one on this forum can give that insight. No one here has access to the relevant business data that would be required to understand this. Even if someone does have access, it's unlikely they are at liberty to share.