Did you not watch last night's game?
Butler's coach said that taking charges are like their blocked shots. They don't have a shot blocker, yet they play pretty darn good defense. Kelvin rarely had a shot blocker, and his teams always played good defense. Defense is about more than steals and blocks. Simply not giving up easy shots (ie, good rotations, getting back on the break) alone can make you pretty good on defense.
Would I love to have a monster shot blocker in the paint? Sure. But it isn't a requirement for being good on defense.