I believe it's the opposite actually.
lack of online will starve people for competition, and they will want to travel more often to fill that void.
Do you know why SSBM has lasted over a decade and can still pull hundreds at national tournaments?
Because they have NO online.
Everyone who loves the game MUST travel, and MUST build a scene.
when it comes to having online always at your fingertips, people don't feel the need to travel to fill this "void" not to mention you MUSt be at tournaments to be good.
while online, you can just keep playing that til you feel like you can hold your own really well in a tournament environment.