There are two other things that matter:
- European municipalities (big business for BMW) usually prefer to buy smaller displacement bikes (remember the K75??)
- In order to go fast, you do not need large displacement. Horsepower can also be made from rpm (P = M x 2? n). If you look at the automotive industry, Europe always had smaller displacement engines, even in fast cars. And small
displacements translate into better efficiency and thus better fuel economy. Something desirable with higher fuel prices in Europe.