"But the idea that late odds drops are not happening is not accurate"

Not saying that at all.

The late bet downs do not always win.

If one horse gets bet down, then other odds must rise.
Which means some "Not Bet Downs" where odds RISE win.

I think you are not looking for those types.

The "WHALES" may just be better handicappers. The fact that they spent money to build a better mousetrap is no different that the hedgehogger quant guys on Wall Street that build a superior trading model.

What I find unfair (and I have heard this but have yet to see hard evidence) is that the "WHALES" have access to Pool data that the average player cannot see.

If the WHALES simply take advantage of overlays based on their probable odds calculation,....Good Luck.
If a WHALE hypothetically "bets down" an exacta, tri, pick 3 or 4.....then the potential payoffs for the combinations not being bet go UP in price.

Think one has to examine the payoff data for payouts that are overly generous as well as for the ones that seemed to "SHORT"

First, one has to figure what are "FAIR ODDS" for a DD, TRI, EXACTA, Pick 3, Pick 4 based on field size and odds.
Never see any data like this published.
Just the customary a DD should pay a parlay plus 10% etc.

And finally, it is a good thing to calculate the probably odds based on DD pools etc.
But show me how you use that concept to cash a bet??