Didn't Bayern already say he's staying this summer and they'd rather keep him one more season and let his contract expire than leave in a year on a free?
Nope. There have been a ton of bs rumors about the potential contract extensions and what will happen since before even Neuer got his deal done.
I remember 2 months ago when the same guy that just had the Sane transfer first had Thiago signing an extension in the next few days basically.
I would be surprised if they let Thiago and/or Alaba let walk for free unless there is no real market for these guys (which is possible due to their high salary demands and limited choices they would probably accept) at the price Bayern would want (probably atleast 35-40M each)..
Honestly Alaba as great as he has been as CB is somewhat replaceable if Hernandez can ever live up to his reputation and stay healthy.
Between him, Süle, Boateng, Pavard and Kouassi as well as the rumored interest in Upamecano as well as Davies stealing his LB spot for good, Bayern can afford to lose him.
Thiago would be tougher but between Kimmich (my dream of him going back to RB seems to be dead for good), Goretzka and Tolisso (if he stays), as well as Cuisance (if he stays) and potentially Kouassi, Bayern could also survive that assuming they use the money they get for these guys to bring in some replacements (Zakaria, Havertz (unlikely), Aouar, Upamecano, etc.).