Ahh that makes sense then.
Don't think the AB cap needs raising though, as 50 is still very high.
Just for interest's sake, It is technically possible for a single bard+cleric character to hit the cap, but they'd have to be going out of their way to stack magical AB - so it won't happen in most cases.
An example would be cleric16/bard4/ssinger10/lyrist10 with artist and time domain using a longbow with all buffs up.
+15 Longbow AB
+10 Inspire courage (with inspirational boost and feats - 5 + 2 + 1 + 1 + 1)
+4 G. Heroism
+2 Blessed aim
+4 Bless (CL40)
+5 Divine Favor (CL40)
+2 Aid and Prayer
+4 Recitation and battletide
+1 Expert tactician
+2 high CL haste
For a total of 51 magic AB.
Other than True Strike - Groups, players using Thieves Friend or Intuitive Attack based characters can also hit this 50 AB cap.
As for the saving throw cap, I think the only case where it really matters in-game now is vs grimy cube petrification in illithid keep, and for warlocks using dark one's own luck. In most other cases, DCs are low enough or you can simply get immunity even if you fail the save.