Im not buying the whole “not easy to get into” argument, at least entirely, and the reason will be based partly on conjecture as well as my own experience.
Fighting games have always appealed to me. Examining the basic movelists of characters in practice mode always led me to believe that there was a world of mind games and possibilities to explore, even though I had no comp in my city and no way to verify this belief. Years ago, I first found competition in a little arcade in my college, and there I played a couple of kids, one who was great at mashing throws, and the other who knew his combos. I got my ass handed to me in X-Men vs. Street Fighter and Marvel. It had been the first time I had seen someone do ridicolous combos, and the rate at which he landed them on me and others was just amazing, it was overwhelming. After a few days of having been depressed and overwhelmed, I realized something. I realized that if he could do it, so could I, and the prospect of that Idea made me LOVE IT that much more. I realized I could outcombo him, outsmart him and outplay him, and I went to work on prooving that. And so, after a short while I did, I learned his characters, his combos and his techniques, I learned how to block them correctly, and most importantly? I learned how to turn them against him and use them against him. Despite being overwhelmed at the gameplay mechanics and somehow frightened initially by the idea that maybe I simply couldn’t execute or think as much as others, the motivation to exceed grew and as a result so did my pleasure in playing these games. Difficulty in accessibility is simply not an excuse I buy, as the intended effect is to empower the player to learn it. Im a level 40 Halo 3 player, and while there are ten times as many players playing this game in general than people who play fighters, Im not going to commit to saying that any of the players who supposedly play shooters over fighters because they are easy to get into are anywhere near tournament worthy, nor would they be in Fighters if they played that instead, because they don’t have the mentality or the willingness to do what is necessary to come up victorious. In this does not lie the answer to why fighting games are not in the mainstream, the answer lies in the dying arcades, and mainstream popularity reached by shooters as a result of ridicolous marketing, billions of dollars poured into production and really gay space marines that look cool to prepubescent spoiled kids. But difficulty getting into the game making it so that there’s supposedly less competitive players in fighters than there is in shooters? Not buying it, especially when you start to differentiate people who appear to be competitive and people who truly go above and beyond to win. If a player wants to get better at something, they will, and if they are a pussy, they will stay a pussy, regardless of the game they play, it’s that simple.
Fighting games ARE coming back, and the way they come back is by idiot developers putting more love into the development process, more money in the marketing, developing great netcode along the lines of GGPO (which they are doing) and more money in the polish of it (see SFIV and SCIV and even STHD a simple downloadable game that could).