Odds of Hanging On
Making a profession out of instructing yoga alone is very difficult. To make a living wage, you'll need to teach a heavy load of classes—we're talking several per day. You'll probably need to supplement that with a few wealthy private clients willing to shell out the big bucks because they're too embarrassed or too good to do a group class like the rest of the world.
Be thankful for the agoraphobic but wealthy fitness nuts, because they're the ones who keep your studio open (even if they never actually see it).
Your practice will be important, but your business savvy is what will set you apart (and yes, that's kind of a theme across many careers). Build your client list; build your future financial stability; build a house on a mountaintop and do yoga like it's meant to be done.