It is hard to believe, but studies have shown that a rod bushing/bearing running on a film of oil actually has less friction than a roller bearing. Besides, it is MUCH cheaper.

They made a roller bearing crankshaft for Volkswagen engines, but had a lot of trouble with it. It had to be pressed together like a two stroke crank is, and it kept twisting at the press together joints. It came with a warning to never, ever "dump the clutch" as that would twist the crank.

AV8TOR