I'd take money on his retirement at the next Fed election. We'll probably find his successor no better.
As it's unlikely that the Senate voting system is going to be changed, then the best thing for GA would be to consult the 'vote whisperer,' and stand a Senate candidate who is committed to supporting aviation, (amongst other sensible and attractive policies). The Senate is where the power resides, and to have someone with ability there would be far better than a party backbencher who has to toe-the-line. happy days,