I have been in racing, time trials and aerodynamic effects on equipment and position since 2008. I have no idea who the "low as you can go crowd is". Certainly, not anyone I know or UCI pro riders competing in Europe.
The gold standard for aero testing cyclists position and equipment is in low speed wind tunnels followed by other techniques such as coast down tests or recording power and speed at the velodrome and calculating CdA.
One technique is to take a picture of the front of a cyclist in different positions and calculate the frontal area. In general, the starting point would be when the frontal area is the smallest. Then one begins to run tests.
Around 2012, Velo Sports Center, the indoor velodrome in Carson, CA put wireless sensors under the track and partnered with a firm that had developed an algorithm that used speed and power data collected from the sensors embedded in the track to instantaneously calculate CdA as a rider rode around the track. I signed up as a beta tester.
The aero session began with an assessment of my flexibility and my feet. Interestingly, the foot position in the cycling shoe matters since it will determine the knee position and whether the knees track correctly as one pedals. I had custom orthotics that a pediatrist had made for my cycling shoes so that foot was perfect in my shoes. In the studio, we put my bike on the trainer and began the fit process to set up the least frontal area position which at the time seemed really low to me. However, I was within the hip angles in the data base the fitter had for UCI pro and international riders AND my body mechanics should allow that position.
From the studio, we went to the track and began doing runs where we tested different seat to bar drops, arm width and etc. As I remember we could slightly raise my aerobars slightly without changing CdA. We then tested helmets and skin suits. There was a new helmet on the market that tested fast in tunnels. I tried it and I tested the same as the current aero helmet that I owned.
The other thing we tested was head position. I did runs where I put my head where I thought it should be and then the operator told me to lower it by lowering my neck. The CdA dropped. The ability to turtle ones head and keep it that way is key to an excellent aero position.
Now that I am all dressed up, can I actually move in my new clothes?
The answer was no. For me, it has taken months and years of strength and adaptation to ride in a perfect aero position while breathing and generating power. Many times cyclists try to improve their riding position to lower CdA and find that they cannot ride it.
Since we have the low speed wind tunnel in San Diego, it is popular for UCI pros to test in the wind tunnel and then go to Velo Sports Center to see if they can actually ride the position. And many find that they have to modify it.
One of the aspects of timed events racing that I find challenging and interesting is going after constant improvement in my aero position, execution skills and power production to improve my times.
The other aspect of aerodynamics is the effect of the rider on the bicycle and crosswind. My body dominates my CdA. Gains that show up in the wind tunnel when testing equipment seem to reduce when I put my body on the bicycle and put on the new equipment. Why? My body creates a pressure wave ahead of the bike such that the impact of the bike, bars and wheels diminish. They contribute but to a less extent. It is also possible to put equipment on the bike and the result will be higher CdA or no change. Crosswind generally lowers the CdA of the frame and wheels but slow the cyclist's speed. This is the yaw angle effect. In the tunnel, the bike and rider can be turned to see the effect of cross winds on CdA.
At age 73, at Velo Sports Center (velodrome), this week I was riding my fastest position making solid power. It only took a few years of practice to get there. What I have done over the years is ride my hardest intervals in the most dramatic (aero) position. I ride z2 on the tops, hoods or wherever.. The other thing I do is climb in the most aero position to build strength and adaptation. Yesterday, I did max power intervals on my road bike seated in the drops on a 6% grade. Fun stuff. YMMV.