Flashlights have always been lightyears ahead of bike specific lights in LED technology. Flashlights have always had much longer runtimes and much more brightness at the same time.
If I'm looking - today, not ten years ago - at the products from Fenix, I don't think I would say that their bike lights are "light years behind" some of their mainstream flashlights. Bleeding edge, no, but they have pretty good emitters, batteries, drive circuitry, and build quality - which is what I might expect from a "bike light" made by a company that knows how to make good flashlights. A number of their bike lights have user-replaceable batteries, too.
I agree that there long have been, and continue to be, a lot of "bike lights" sold that are deeply inferior to a lot of mainstream "good flashlights".