well a lot of things are quantifiable. like how effective catchers are at framing pitches (there's actually a metric for this that places a number value on runs the catcher saves or costs pitchers based on how well they frame pitches). there's WP+PB/(total pitches), which isn't great in a small sample size, but is useful over the long run and when you compare this with other catchers facing the same pitchers. same with how frequently players run - a catcher who doesn't have a lot of SB attempts against is probably a good receiver, and a catcher who consistently throws out more baserunners than his peers on the same roster is probably a good receiver. i have no idea what "quarterbacking the infield defense" means; generally the bench has a lot more to do with infield defense than the catcher. when you take the pitch framing thing into account, the stats on the running game, stats on wild pitch percentage and passed ball percentage, comparing these to other catchers on the same rosters, yes you can get a pretty good idea, numbers-wise, of how good a catcher is defensively. and your original statement is nonsense anyway, because it seems to assume that the sabermetric community completely shuns or doesn't understand scouting.