"Lots of direct smoke & fire around Slovenia re: Aderlass."  Oregon too, but drug tests seem to only come with THC regularly. 

There is another factor here - genetic body types.  There are peoples (before civilization, no one would be offended calling them tribes) that have body types very well suited their native environments and for specific activities.  Some sports (and certain positions of team sports) are dominated by people from certain places.  Marathons and the high altitudes of Kenya.

In cycling - the small people from the high altitudes of Columbia dominate in the mountains.  The Belgians and Dutch I have known, although not cyclists at all, certainly look like powerful roleurs.  (OC, you do not look physically like one of my Dutch friends.  This isn't a universal statement.)

I am reading a book written by one of the strongest players in the NFL.  He talks openly about his ancestors being slaves.  I am pretty certain, those slaves came from West African tribes noted for their size and strength and that commanded high prices as field hands.  (At 11 years old, he lifted a tractor that was about to crush his granddad.)

Cycling also goes through changes.  3 week tours sometimes favor all-arounders and power, sometimes more altitude.  A flow of changes in team tactics.  Rule changes.  The popularity of the various types of racing.  So best body types for the sport isn't a constant.

I am not ruling out the drug enhancements.  We all know the EPO years, have wondered when we are going to hear what Sky did.  Belgians?  Colombia with its huge domestic coca scene (I doubt the riders use a lot of cocaine but that does create a "culture")...  Right now, the Tour Colombians are looking quite real!  Quintana and Bernal not looking super-human at all.  But being walked on by Slovenians?  Hmmm.  Granted, both of those Colombians have crashed hard recently, Quintana very hard back in July.

Another aspect of the flow of nationalities in cycling is political/circumstantial.  As cycling becomes both known and possible as a way out for blue collar young men and one of their countrymen leads the way as an example, that country then becomes a source of young men motivated to "get out" like the Blacks of inner city US through basketball.  (Now those young men often are not grounded in the middleclass white US notion of "clean and fair play".  The "rules"  of the outdoor courts of the US inner city and the roads of eastern Europe are quite unlike the prep school I played my sports at.  We played to win cleanly.  They play to get out.  If that means an elbow to a place where it doesn't belong or taking this or that, well if that young man can get out, make good money and send some to his mom, isn't that good?

No answers here.  But I try to keep an open heart.  Yes, I want better testing and a cleaner sport but that is as much so those young men don't have to poison themselves in their quest.  The early EPO deaths, Lyle Alzedo, Cortez Kennedy.  Shouldn't happen.  Ex-players and riders should be able to live a decent life.

Ben