Power limits for LA small blocks?

Back to why are the 4 cylinder imports able to make so much power ? Cylinder head design with overhead cams and low reciprocating weight, which equals high RPMs. They make horsepower at 10-12k rpms. Try to do that with a V-8 and keep it together. That is the short and sweet as to why they do what they do. Of course if $$ is no object you can eventually make the power with durability ( wait, what about NASCAR engines )