15 wisdom at level 1
+5 for level ups (4, 8, 12, 16 ,20)
+5 inherit bonus
You have a 25 wisdom now at level 20. If you allow players to qualify for feats using magic items (obviously you can't use the feat if you loose the said magic item, a perpiat of wisdom +6) then it is fairly easy to qualify for. If you don't the by either leveling up a couple times are taking an ability boosting feat 27 or 30 (or starting off with better that a 15 wisdom at level one) then you can gain it prelevel 30.
Just an example. High abilities in one or two ability scores aren't hard to get by level 20.