Why haven't they switched over to the Outer BH and Inner FH?
Even though some players are especially known to have great FH's or BH's doesn't mean they're not also great on the other wing, it's a misconception, it's just that one wing just stands out like wow. A blade is one unit and most players prefer to have the same feel and predictability on both wings when it comes to the base (blade) and make whatever adjustment necessary with the rubbers (different rubbers or same on both sides).
Personally, it never mattered too much what blade I used on my FH as it was my stronger wing, but it mattered a lot for my BH for some reason. So when I switched to the IF ZLC, I immediately loved the feel of it on my BH and not as much on my FH at first compared to an ALC blade. My BH improved tremendously thanks to the feel and confidence the blade gave me, and of course, lots of training, to the point where my BH got as good (some say better) than my FH. My FH got used to the blade quickly, it didn't get worse, in fact it got better too (especially switching from loops to flat hits), it's just that my BH got exponentially better in comparison.
To conclude, the specs of a blade or a rubber don't matter until you've tried it for yourself over a good amount of time, what matters is feel, how you connect with it, it's personal, everyone is different, for some it doesn't matter much, for some it makes a big difference. Go with what feels good, not what other people tell you or what conceptions you think you have. I've liked some setups before, but never as much as the one I've been using for the past year. I still try blades and rubbers here and there, not to find the next best thing, just to try and gain knowledge, because they only prove that I like my setup a ton more and there's no immediate need for me to change. If something feels right/works for you, don't change it, don't hurt your head and spend all this time trying to find the next best thing, use that energy training instead!