Why haven’t winning Kentucky Derby times improved more?

is it interesting that the winner’s time on average hasn’t improved that much over 121 runnings at the current length?

The winner of the 1896 Kentucky Derby, the first run at the current length, was Ben Brush.  He ran in 2:07.75.  Only 4.16 seconds off the most recent winner, Always Dreaming.

Always Dreaming ran in 2:03.59.  Crummy conditions, it’s true, but in 2015, on a nice day, American Pharaoh’s still only at 2:03.02.

Four seconds ahead of 1896.  Would’ve lost to 1931’s Twenty Grand.

Twenty Grand finished in 2:01.8, which would stay the record until 1941, when Whirlaway shaved off .2, coming in at 2:01.40.

Whirlaway’s 1941 time that would’ve beaten 62 of the 76 winners since then.

Whirlaway and the great Barbaro in 2006, champions from sixty years apart, put in times less than .05 seconds off from each other.

source: KYbluegrass on Wiki

The winning time for the Kentucky Derby has hovered around 2:02 for sixty years.

In 1973 Secretariat broke the two-minute barrier.  A special horse.  It’s still the record.  Monarchos cracked two minutes in 2001.

In the Kentucky Derby, the top ten all time fastest finishers represent six different decades.

Compare to humans:

A world champion human mile runner from 1941 could not hang with any serious Olympic miler of the current era. Champion human mile times have improved by about thirty seconds.

Maybe that’s the wrong comparison.  The Kentucky Derby is a sprint and tiny differences are significant.

OK.  Say like the 100 meter dash?

Usain Bolt would beat any 100 meter dasher from the 1940s.  He’s a special case, the best ever, but even the sixth place finisher at the 2016 finals would’ve been breaking the world record from ten years before.  Nobody from the ’80s would’ve come close, let alone anyone from the ’40s.

The world record holder in the 100 meter dash from the 1940s wouldn’t even make the finals at the 2016 Olympics.

You have to go down into the 200s of fastest Olympic times  before anyone from before 1990 shows up:

Olympic gold medal times have improved by about 10% on what they were in the early 1900s.  That’s in a race that lasts around ten seconds.

The human race that timewise is the closest to the derby, around two minutes, is the 800 meter dash.

Again let’s use the Olympics.  Edwin Flack of Australia won in 1896 with a time of 2:11.  By the 1930s he would’ve been smoked.  By then, Tommy Hampson could run 1:49.7.

By the 1980s Hampson would’ve barely made the finals.  By 2016 David Rudisha of Kenya is finishing at 1:42.15, a 29 second improvement over Flack.

Rudisha is very special of course.  But even Yiech Biel of the Refugee Olympic Team, last finisher in his early heat, put up a time of 1:54.67, a healthy 17 seconds ahead of Flack.

Maybe that’s the wrong comparison.  The Kentucky Derby isn’t a world record, it’s a specific race under changing conditions that can be favorable or unfavorable.

Fair point but aren’t Olympic finals conditions variable?

But the Kentucky Derby’s a one-off, you only run it once (when you are three years old)

That might be interesting but also so what?  Shouldn’t that mean even more variance?

More: the Derby-length (1 1/4 mile) world record run by a horse hasn’t broken 1:57.  Closest was in 1980.

The world record time for a horse running this distance hasn’t improved in thirty-eight years.  Meanwhile human 100 meter dash times progress pretty neatly.

So here’s my question:

Has human running improved more than horse running? 

Why? 

One theory: horse racing reached peak times quickly and stayed there because there’s more money in it.

Are my assumptions wrong?  Very open to that, maybe average racehorse times have improved, I don’t know and I’m not sure I’m gonna bother finding out!

Please, weigh in if you have a take.

Here’s my second question:

is this interesting?