With Alaba, I'm not concerned about money either. I fully expect our board to be sane enough to know that Alaba is the kind of player worth going to the limit for, and I'm sure they fully grasp his value, which is enormous.
I'm more concerned about his personal ambitions and whether they are completely satisfied by staying at Bayern, considering that
a) he seems to be not 100% happy with the role he's played, at least perspectively, since one keeps reading he'd like to either play in midfield or at least have a more reliably defined position. Not sure how seriously to take all this though.
and b) literally every top club would be hellbent on signing him given the opportunity; and I'm not worried so much about England as about Real, who are after him hard, and Barca, who'd likely jump on any opportunity too. Real and Barca are undeniably serious competition for every player, I'll ignore his supposed childhood affection for Arsenal
The thing that puzzles me though, and also kind of relaxes me, is that I don't really see him starting in midfield for those clubs. They would likely sign him as a left back too, just as I'd expect him to play as left back under any new coach for us.
So ironically, the crazy, variable, rather unprecedented, and slightly chaotic hybrid left-back/midfielder/box-to-box-centre-back/attacking midfielder roles Pep liked to use him in seemed to me a pretty good way to incorporate all his qualities and get him highly involved beyond the left back position.