I don't know why anyone would worry about car engines in bikes. "Boss Hawgs" ain't going to take over the world.
Perhaps the Ecotec? GM engine would be a threat, since it looks just like a DOHC bike engine and has factory parts that can take it past 1000HP, but seriously, that is only a concern to a very limited number of classes.
Bike engines in cars though is another matter. This potentially eliminates those who want to push the limits with the small displacement car engines, and isn't likely to improve bike engine technology. I don't see an "upside" to it. Yes, we all know that more RPM is more better, and when you remove the limitations of what is required to propel a 2500lb car for 100,000 miles on the street and meet SLEV/CAFE/EPA standards, you can do a lot more with an engine at the OEM design stage. There never will be a production car engine that is going to compete simply because there will never be a need for a 13,000 rpm engine for a 600lb car with smog exempt status. Only from-the-ground-up race engines could. Or motorcycle engines. You might have noticed that Suzuki does not put the Busa engine in their cars. Seems logical that they would. But nobody wants a 15mpg economy car. Suzuki DOES make car engines in the displacement range of the Busa, and they work very well in cars.