You can grow anywhere if your willing to put in the work, time and effort to put yourself out there. Don't depend on a programme or "thing" to make your channel grow.
Go out and do it yourself, yeah it helps but you won't grow until YOU decide to kick yourself into gear.
As for YouTube Gaming I haven't really looked into it much to know and I don;t know of any success stories just yet but if its an opening market by all means go at it full steam ahead.