It's interesting that nobody has really focused the key comment regarding the fight; he lost sight. There is very little actual information regarding the geometry of the fight or relative E states so it's very hard to say which aircraft was really superior, what is clear is that Johnson made a bad mistake. How long did Johnson lose sight and what was his response? When someone loses sight 99.9% of the time they will ease their pull so they can look around, especially if they lost sight because they started to black out. Even if this only took a few seconds, a few seconds of the 190 pulling his best turn while the Spit pulled less can easily account for the angles the 190 made and, once in a position of advantage, any aircraft is tough to shake regardless of which is the better turning aircraft.
Also, you have to take anecdotal information with a very, very, large grain of salt. The way a pilot perceives a fight is wrong far more than it is ever right. There are many reasons why this is so based on both psychology and physiology. The human brain, especially under severe stress, is just not an accurate recorder of facts but focuses on perceptions. You might, for instance, think that Johnson's interpretation of the 190's capabilities are really somewhat colored by the fact he's covering or minimizing his own mistake, either consciously or subconsciously. I'm not saying this is a fact in this case as there's no way to really know, but it is a consideration when reading anecdotes.
This is why we now have things like the TACTS Range and rely strongly on HUD recorders to reconstruct fights. It's also one of the reasons NFWS discusses fights as "the F14 did this, the F5 did that" rather than "wohooo, Maverick killed Joker". It takes some of the personality and ego out of a fight (the movie not withstanding) leading to more accurate reconstruction (as well as more intelligent decisions during a fight). TACTS accurately records the entire flight and can be used almost exactly the same way we use the film viewer. Modern HUD tapes are also very different from the gun cameras of WWII and will record the entire fight, including all the aircraft info on the HUD, shots, and voice.
The very first thing to do after a flight and before the debrief is to pop in the HUD tape and reconstruct what really happened from your own perspective and then, during the debrief, compare tapes to help build the real picture as best as is possible. The results can be very surprising even for experienced pilots and your credibility can be questioned should you have "forgotten" to turn on your HUD recorder and make some claim not supported by hard data.
On another subject, I find the various descriptions of the 190's stall warning interesting. The comment that when the ailerons are properly rigged the 190 gives good stall warning is significant. It seems to indicate that the 190's stall may have a tendency to begin at the wingtip vice the wingroot unless the ailerons are exactly right. This would not be a good thing as field conditions and airframe stresses would make proper rigging difficult to maintain and therefore, the average pilot would be forced to deal with poor stall warning and abrupt stall characteristics.