But what Patrick says is right: consulting is a GREAT opportunity right now for iOS devs.
However, where I disagree with him is this pivotal phrase: "Should there ever be a gap…" No no no!
Don't wait for there to be a gap. The absolute worst time to be prospecting for client work is when you need it.
I'm all for throwing your energy into growing your existing revenues, but there's no way I would have ever done what you did and I have no kids and no mortgage. We consulted while we built up our app -- and it was stressful as hell but those big fat checks were a godsend. I can't even imagine trying to squeak by on $3k pre-tax with a spouse much less kids. Or with non-subscription income.
If you read the other things I write, you'll know I'm anti-magical thinking and rainbow gum drops and fairy dust. You know, unicorns, like the one being impaled by Mr Pointy the Narwhal of Truth on my blog header (http://unicornfree.com).
Well, this is unicorns in action, dude. The deep down, heartfelt belief that if we just throw yourself at something hard enough, we must succeed, is a horrible thing we internalize from movies and TV shows. It makes great television but it's not the truth.
If you fail to protect yourself & your family, income-wise, all the joy from working on your own thing will be worthless. You will feel so terrible, and be in such stress, that you will long for the days of your boring, unrewarding job. True money stress (not "I can't afford this luxury and I want it now!" but REAL stress) is worse than almost any career dissatisfaction. Worrying about your basic needs is way more time consuming and soul-sucking than a crummy job.
So:
Bust ass to pick up consulting gigs now. Make the transition as seamless as possible. Build up a client base and you can charge more and more for better and better clients and fewer and fewer hours. It'll still be consulting, it'll still be working for somebody else, but for a while, getting paid double and triple the amount is novel enough that you'll cope.
You'll thank me later.