I have a few different thoughts here (I fly the K-4 frequently):
1. This K-4 pilot sounds like he's still learning how to fly it and how to aim the tater. He could easily have out-climbed you instead of the more traditional horizontal extension (not so much if you were in the ufo-like spit16). I see lots of 51 pilots who are in the same situation: they know how to get lots of altitude and fly really fast, but can never convert their energy into a high % gun solution. If it were agent360, pjk, or mondego they probably would have killed you on the first or second pass. 
2. It's not just his $15, but also the strengths of his aircraft. Spitfire pilots turn and turn like like a merry-go-round, but we rarely criticize them for it like we criticize a 51 for running. Maybe if you and the other spit pilots promise not to turn so much, we'll promise not to fly so fast. 
3. Isn't it boring? Well, yes and no. Some of us get tired of the simple latch-on-his-6-and-don't-let-go-til-he's-dead approach that you probably call a "fight." It's a youthful approach to air-combat, but a limited one that tends to the horizontal, and long tracking shots. Appreciate this point: whereas you have many seconds to saddle up on a bandit and fire in your spitfire, that K-4 pilot has a firing window of about .25 seconds every time he gets to fire the tater. If he misses, that spitfire has already turned around on his 6 to chase him! 
What double-speak. 
My final point should be this: hypothetically, that K-4 pilot might have been decent in a Spitfire, but he needs time to learn something different and...more challenging. 
You are describing a timid K4 pilot. There are a boatload of 109 drivers out there now, many of em wearing Muppet or BK tags that do amazing things in them because they want to fight and push the G14s and K4s to the limit. I can think of a bunch of 38 drivers who go looking for a fight too and push those big targets as far as they can to learn what they can do, not avoid it.
In the end it's a battle of game play mentality. For many of us, we understand that our time is limited to fly, we know that death is not real here and that our planes have an unlimited supply. We also know that the joy of the game is testing yourself against another human being in a cartoon plane.
There is another group, many who have much more time to fly, who approach it from the idea that 'living' means something and that fighting from only the advantage is the way to go. It's their dime, so go for it, but it's hard for many of us to understand as that's not the challenge for us.
A good example from the other night. Two of us upped to check a large dar bar to the south of the base. We ran into olskool in a 109 and someone else in a Zeke. They were slightly above us and it appeared that both were coming down. Olskool did and got a hit on me. The guy with me ended up lock in with Olskool so I turned to the Zeke as it appeared he was coming down. The second I turned towards him, he zoomed back up. Olskool and the other guy had a knock down drag out and Olskool finally went down. The Zeke left him hanging. Even sadder is the Zeke kept moving towards our base and then dove in trying to vulch only to die to the ack.
