Because NRS actually has been putting out quality games for casuals such as mortal kombat. Unfortunately, they have a few divergences from traditional games that segments of the community don't like, such as a block button. So a lot of the well regarded fighting games are still from japanese devs. Examples are street fighter from capcom, guilty gear from arcsys, tekken from namco. None of which had the full package triple a game experience before sf6. Unfortunately western fighting games might have been better for consumers, but for a long time and often even now people within the fgc have not considered them real fighting games. Same applies to smash, though an additional part of the divide there is because they're very secular. Smashers play only smash and don't play other games often, where an evo entrant this year was likely to enter both sf6 and strive.