Kentucky Derby -- anything with less bang for the buck? [Revisited]

Requiring racehorses to be a result of live cover doesn’t seem to meet any of the criteria you just wrote.

I loves me some Keanland!

No, it’d be eugenics.

Unless they changed it recently, standard takeout is 15%. The rest is rounding error. The posted odds are always an approximation in parimutuel betting, and they can even change slightly after the race starts as the final bets are tabulated.