What's the driver for the US/UK 30% price diff on new bikes?
I don't know. I started looking for reasons but haven't found much yet.
For a true comparison, we should be comparing out the door pricing. US dealers charge substantial fees and taxes, an extra $1000 or more on a $6k bike isn't uncommon. Perhaps some of that is rolled into list price in the UK?
Another factor is probably transportation. Anything coming from Asia by sea, has a closer, easier journey over the Pacific to CA, vs around Cape Hope to European ports. Insurance rates are probably lower for the pacific journey.
I also think that the UK market is more regulated than the US, there are more riders using their machines as transportation, vs recreation, and the 2nd hand market is less populous. All these factors support higher pricing, as does the existence of fewer dealers.