Getting up there in age I suspect.
Takes a lot to put yourself out there and go to battle in the political trenches.
There is also some baggage regarding the name Brady that will rile up the opposition to gun control.
That... ^^^
The name Brady is now indelibly conflated with bans and confiscation, and the new tactic has been to double down on "common sense safety" and "third way" moderate shill groups.
So now "Brady" is tainted and has to be back-burnered. They only have limited usefulness for the rare times they might help fundraise from the hard corps anti-gun base.
The good news of course is that to date, the new strategy of the third-way moderate shill groups has fallen largely flat, except where they had an anti-gun majority politically in blue states, and Colorado is still in play.
I know the NY and other blue state folks are hurting, but with the existing bans that didn't expire in 2004, we've mostly written you off like California, sad to say. You're going to need some sort of grass-roots program that's so powerful that it overrides the domination of the cities.
Colorado is still in play, and hopefully Hickenlooper is next to pay the price for the bans there.
Fortunately for us, the whole "Zumbo Affair" was an even more important watershed moment for RKBA, because it truly defined the .mil and tactical-style wing of the gun culture as dominant over the "sporting"/Fudd side, and the anti's are just tone-deaf to the point that the moderate-shill strategy won't work well because of it.