From my experience, if the brewster pilot is good, it often results in a stale-mate, as the 190 struggles to get an angle to place a shot, and the brewster struggles to get a shot in time (after a reversal etc..). Sometimes I have seen pilots in brewsters make amazing shots from 600+ out but that is as much about the pilots as it is about the guns.
That is my point. The speed of the Fw190D-9 means that with only slight skill he can make pass after pass without being exposed to return fight. Now, being of slight skill his passes will likely result in nothing, but I don't find his use of speed any more difficult than I find the B239 driver's use of turning.
Frankly, having done both, using turning, rolling and sliding to avoid being hit by the faster plane takes a lot more skill and SA than just using speed to avoid being hit by the slow plane does.
Learning to use the fast plane's attributes offensively so as to set up successful kill shots is harder than learning to use a slower, turny plane to set up kill shots on targets with less E than it has.
Defensively, speed is easier, offensively, turning is easier. The qualifications for each of those is that you speed becomes harder defensively when a turny plane converts altitude to speed to overtake the faster plane and that using turning ability to set up offensive attacks is harder if the target does not consent to slow down.