Both Melee and Brawl have awesome communities. I really wonder what you base the death of a community on if not strickly on the outside perception of rival communities. I base my observation of the community on what I witness at tournaments. Last weekend I did a Brawl tourney in MD/VA, and it was awesome, and though I missed it like 1/3rd of the people at the tournament went out to eat together afterwards. About a month ago I held my own tournament in Ohio, and when it was down I had about half the people stay just to eat and drink and have fun together. I've been to tons of tournaments in both Melee and Brawl where I'm housed by random people I haven't met, where I'm driven by people who lives hours from me, and where I meet people who I would in my everyday life probably not be privileged enough to meet. Smash is one of the only places where you can live this 'counter culture' type of lifestyle. It doesn't matter how good you are, there is a place for you somewhere in the Smash community.
I play Brawl competitively, it is both fun, exciting, demanding mentally, and for me also somewhat physically (Diddy is likely more demanding then Peach was for me in Melee). One of the things I like about Brawl is that it's slower pace allows for a very clear perception of what strategies are being employed and what strategies are being used to counter said strategies. I litterally have written down information that looks almost like my old chess notes about Brawl (and I did in Melee but just to a lesser extent). Melee I view as basically the same, except for most people it is more demanding physically, and the technical challenge can be an attraction to the game (actually this was one of my chief reasons for playing Melee competitively back in the day).
Both games have highly consistent winners, so saying anything along the lines of "not competitive" or "easy to get good at" is a joke, since it clearly ISN'T easy to get good at either game and if it were then why has it been 4 months since M2K lost a Brawl tournament (and why has he only lost 1 Melee tournament in the last year, and his loss comes to the same player that ended his previous 1st place streak).
The best way to tell if a game is competitive is simply asking if there are consistent winners. If there are consistent winners then that means that the better players win, which is all you need for a game to be competitive. Consistent winners means someone is doing something MORE RIGHT then the opponent and is therefor better. What that is and whether what they are doing is "dumb" or "annoying" or "not fun" is another story, but at the end of the day anyone who says either Smash game isn't competitive I just tell them to look at the consistent results and if it isn't competitive then go ahead and try and win.