6* Pitchers - Do They Suck?

I always see to get a disproportionatly good result from this Kaat card--better than I'd expect from his NERP or BR ratings.

I decided to check out my actual results from 3.88 M Kaat pitching on 80, 100 & 60M teams. These results were mostly achieved in lefty parks.
80M Leagues
17-15 w/ 4.33 ERA. League average ERA: 4.16
20-11 w/ 5.08 ERA. League average ERA: 5.09
19-12 w/ 5.86 ERA. League average ERA: 4.46
14-12 w/ 4.84 ERA. League average ERA: 4.47

100M Leagues
16-13 w/ 5.49 ERA. League average ERA: 4.59

60M Leagues
21-11 w/ 4.42 ERA. League average ERA: 4.16
Net results: Kaat had no losing seasons, while tossing two 20 game winners and one 19 game winner. His ERA generally close to league average, though a couple were well above. As I suggested, he was no doubt helped by pitching against the other teams' #4. In six seasons, his total W/L was 107-74, for a .591 w/l percentage. The teams he pitched on generally hit pretty well, relative to the league. That hitting was helped, of course, by Kaat's low price.
Even acknowledging all of these factors, Kaat 3.88M generally seems to perform for me better than one could reasonably expect. Certainly his w/l % is better than these teams overall, including the performance of more expensive pitchers. Maybe it's a skewed sample, but I look on Kaat as a lucky charm.

I know he's not a S6* but rather S8*, but wouldn't Drysdale 4.06 card be an overall better value than Kaat ?

(80 total OBP vs. 90 total OBP, by my calculations)....also a (much) better hitter, with similar peripherals and only 10 worse error rating

thoughts ?