*puts on the Outlandish-Theory-Goggles*
This is why I think, that Frank being a "trollish mastermind" isn't that unlikely. It seems a bit strange that he (or anyone, really) puts up with Brianna like this, indulging and most likely paying for every fleeting whim she has... Except if you take into account, that he couldn't stand that his previous wife was better at writing than he was. Of course, this info comes from the mouth of a disgruntled ex, but I don't think it is that far off: Frank can't stand to be with someone who is (on their own) more successful than he is.
I think Frank needs Brianna to be a screw-up, perhaps as some form of self-assurance. He needs to see that -without his guidance and support- she would fail, crash and burn in the most beautiful firework of autism imaginable. It doesn't matter, if a lot of idiots out there think she's some kind of awesome game-design-writer-politician-feminist-something-something. Without Frank Brianna would share the same social step as Phil and Chris by now, and Franks knows that. Heck, he probably even feels accomplished to be the guy in the background who put a monkey in a dress and makes it run for congress, while the White Knights are cheering for it.
And besides: Every other partner, who is half-rooted in reality, would have long seen that Brianna is unfit for congress. That even if you support her, it only can end in disaster. The only logical conclusion is not to support that whim of her, but to dissuade her from doing so, have one of the dreaded 'honest talks', you have in serious relationships.
Even with your job being shitting wads of money, so you can hold your own ghoul pretending to be a feminist icon as a hobby, your rose colored-glasses can't be that thick to not see, that Brianna will screw up her Wu-for-congress-play-pretend ...
...except of course, it is in fact your hobby to have a tight, yet invisible leash on her, and train her like a good dog to be what she is.
TL;DR of this theory is: Frank and Brianna are co-depended. Brianna needs Frank to continue escaping the harshness of reality, the fact that she is a massive screw-up, and so she can keep being the 'nine-year-old boy who play-pretends to be a feminist-icon' forever. While Frank needs some human animal to train and guide, to be something what she possibly can't be without him, and only him.
