RE: Why don't we have more 4 stroke gassers?
There are a lot of 4 stroke gas engines out there right now but they are all at a premium price point. Nothing wrong with that but most cannot or will not afford them.
They are becoming more common now so you can expect to see more manufacturers bringing them to the market.
For now you will only see the 4 stroke engines coming from the companies that make top of the line engines or specialize in 4 strokes.
I'm a little surprised that the Chinese haven't copied a four stroke yet.