I'd say the average player goes to 2 SJCs a year (when SJCs were common)... very rarely did we say players going to 3 or more. It has been confirmed that SJCs have "more than double" (Andy's exact quote) the prizing of prior SJCs; so with that being said, going to one SJC alone and doing well could make up for the "lack" of prizing in Jonins and could also cut back on travel costs for people who [would] travel to many SJCs.
Plus, people are strongly underestimating the value of the promos that will be given out at these events. Kevin's card is a money card, as will be the Hinata / Sakura promo. Plus they're giving out the NEW game which looks far superior than last season's junk game. Going to one or two jonins and then at least 1 SJC is more than enough for a player to get their competitive fix (and to make $$$). It isn't perfect, but it's good for what it is. I personally think the prizing THIS season is superior to last year (I'd rather have many of those promos than the junk game; because I know I can make money off those promos).
tl;dr -- Competitive scene is no where near dead in this game - especially since it's on the cusp of the biggest fanboy set of all time. Game is still great (albeit we need a rogue list by hopefully set 28's release) and I can't see it dying for a while.