That's the point...

Nobody is standing up and claiming XXX boat is a ratings beater!

The tough part of this game is to keep things equal. For instance, if you run unbalanced race courses eg WLWL and then finish up at the weather mark for a last windard. Boats with spins are not favored. Hell, if the RC sets a small course with several laps on a breezy day ... two things will happen, your I20 crew will die and you will have a hell of time sailing to your number because all of the sail change transitions cost you time and are a significant percentage of the race.

Bottom line. Any handicap system (Texel, ISAF Portsmouth) is most accurate when similar boats are rated and raced. EG all spin boats.