The picture shows:
-no water bottles
-no bottle cages
(I bet if you put those factors in, the results woudl be so jumbled that the benifits would be even more indecernable, as to negate any benifit of an aero frame)
I sure know that I wouldn't bet when it comes to that.
A helmet and a face will change the total amount of drag, but I just don't see how it would affect the airflow around the frame, so I'd have to think it only shifts the y-axis.
Bottles and cages could very well work in favor of an aero frame. Maybe the difference between a round tube frame and say the S5 or Neil Pryde is larger once you put the bottles on, because the air is led around them entirely? Not saying that happens, but it could be.
Same goes for cables and housing. Maybe cleanly routed internally the difference grows?
Shifters and bartape might have an effect on the airflow around the HT, especially at higher yaw, but I doubt they'd negate any aero benefit.
I guess it all depends on what side one puts the burden of proof. If you want hard data that a bike with airfoil shaped tubes is faster than one with round tubes in the real world you're always going to find something. If you think that bar tape on or off makes a test useless or just a tad less precise is up to you.
If you accept that an "aero" frame has less drag than a "non-aero" frame I believe you can see a trend in the data which might even be helpful.
What I like is that there really isn't a clear "aero" or "not-aero" distinction any longer. Cervélo had the R3 and the Soloist, where the R3 is the comfy long distance bike and the Soloist is the cheat the wind bike. Right now I ride a Parlee Z5 and race an aluminium Soloist, which is the best of both worlds, IME, but my races are usually short crits with rather smooth roads and not everybody wants two bikes.
Now with the Neil Pryde, for example, it's pretty much right in the middle. I was very surprised how nicely that rode for a bike I had in my mental "aero" drawer. It's definetly not a bone shaker, corners really well, is responsive and could easily built up to 6.8 even with deep wheels. I suppose they made the bike they wanted and then made it as aero as they could given what they had instead of making a bike super aero and then try to figure out how to make it feel like a nice ride.
At that point it really becomes a win-win, not an either this or that.