Mox worked in Japan LAST MONTH.
FTR worked multiple shows in Japan and in England.
Eddie Kingston did the G1.
Gates of Agony and Lance Archer are currently in tag league.
Plus all these guys get to do big matches as part of Forbidden Door.
Further, I really don't think any of these guys are looking to do full tours. When Ospreay "wants to work New Japan," I assume it means he wants to work the Tokyo Dome and maybe one or two other big shows. TK's shown that be very plausible. That's a real difference with WWE, where they've only shown a willingness to work with New Japan on guys already committed there (Good Brothers).
NJPW is absolutely the junior partner at the moment and they know it.