Honestly, I think most of it is because those shows are subbed and, in the case of Jetman, have always been talked of as the greatest things ever. When Japan Hero was around, it seemed like Jetman was that place's favorite show and I think that got into the popular mindset. Though the lack of any real subs is still the problem. A lot of people just aren't comfortable watching a show raw, which you can't blame them for at all. This does lead to some great shows being undervalued and not given enough discussion as some might think they deserve.