No, people don't fly them because they are "easier"... people fly them because they are better. It is plain and simple. Have you ever fought a Spit IX co-E (same starting alt, reasonably close starting speeds) in a 109G-10? You'll find that you will have a very difficult time defeating one if the pilot knows just about anything. For instance.. if the Spit pilot knows to keep turning in one direction once you get on his tail, you had better be real good at deflection shooting. And with the 109s anemic firepower, you better be REAL good at deflection shooting. An "ace" in a Spit IX will kill an "ace" in a 109 every time unless the 109 simply runs away. In that case he still loses, since the goal is to shoot down your enemy, not run from him.
People fly the La-7 because it is the best fast plane. People fly the Spit IX and N1K2 because they are the best slow planes. People fly the P-51 because it isn't half bad, and it has newbie appeal. The newbies go on to "graduate" to the La-7. The fifth plane changes from time to time, but it is usually the Typhoon, because it can kill fuel pretty easily, and a snapshot is a certain kill.
Compare the 109G10 to the La-7 (in game, I couldn't tell you how they stack up in real life). The La-7 is faster, accelerates better, has more firepower, turns better, and climbs just as well. So why on earth would someone fly the 109G10 instead? The obvious (not to mention correct) answer is, they wouldn't. This is why the La-7 usually gets 2-3 times the kills the 109 gets. Actually, the only reason anyone flies any plane other than the La-7, Spit IX, P-51D, or N1K2 is because they think they are good and they wouldn't want anyone to assume it is all because of the plane they are flying. In my opinion of course.