quite rare, certainly genetics, and age/nutrition, many of these 2.5yo bucks and younger maybe have them in their potential, but they never make it.

Also ive seen alot of guy's "droptines" 1 inch drop, or a number of the bottom isn't a drop to me, so real drops even more rare in my view.

Cousin found a shed with 3 monster drops on 1 side, years ago, boy is that awesome to see.

Really if we let those young ones grow up we'd see many more, but by areas etc..genetics I think you'll find higher density zones for drops...