Well let's look at this logically. This is a deal that was announced around the same time as the Activision one:
https://techcrunch.com/2022/01/10/take-two-to-acquire-mobile-gaming-giant-zynga-for-12-7b/
If they really wanted to buy themselves into the mobile space there were cheaper and easier (from a regulatory stance) pathways available at the time.
But we all know it has fuck all to do with mobile.
The problem with your and other's argument is, it's focused
only on mobile. Just because something is a primary focus, or one of the priority motivations behind an action, doesn't mean the secondary reasons or other reasons that fall lower in priority don't have value or are unworthy of consideration.
If they were solely interested in mobile reach, yes, there are other moves that could be made. It's obvious that's not their sole intention, even if they claim it's a big (or perhaps the biggest) reason for the purchase. I'm not saying MS is being honest, nor am I saying they're lying. I'm saying two things can be true at the same time, and one thing isn't always mutually exclusive to another.
If I'm buying Disney, I won't sell Marvel to get it. Nor would I sell Star Wars to get it. CoD is a cash cow, and so is Candy Crush. If I were buying ABK, I wouldn't dream of selling CoD, Candy Crush or even War Craft. I'd consider selling lesser titles or maybe even some old, unused IP, sure. But certainly not those three. It'd be
almost all or nothing. If the deal doesn't go through, that would be terrible for me, but it also leaves me with a lot of cash in the "war chest" to make other moves, going forward.