As you refer to "Outlaw bikers"[1], I suppose you mean bob jobs and choppers? Where the boat anchor is turned into an ill handling torture rack? They make for great eye candy, but are absolutely useless in any practical sense. Sounds more like Microsoft style innovation to me :) [And of course, H-D shamelessly stole their looks from Indian...]
There is actually a lot of true user innovation (as in where the performance of the bike is enhanced in a usable fashion) for the Japanese and Euro performance bikes. Most of the work is done by/for privateer race teams and is to a large extent available to the general public.
[1]A large section of the originals rode Triumphs and Nortons...