The market was highly profitable when it was small supply / big demand and you had good odds that Apple would hand you tons of visibility. Now it's big supply with a terrible signal to noise ratio.

To succeed, it seems that you now either need a mountain of luck, or a killer marketing engine and a fair amount of luck. Mathematically, it seems unattractive compared to other ways of applying the same time and skills unless you have something you're obsessed with building and want to produce irrespective of the outcome probabilities.

E.g. a $1.99 app pays at $1.393, so you need to move 34893.75 paid copies in order to clear a $50,000 gross. For SaaS and the same target, you only need 208.33 customers at $20/mo. The capture difficulty is not identical between cases - but if you have good marketing and are assuming serendipity on either side, it's quite feasible to hit 208 customers. Furthermore, it's often easier to grow once you get there, and it's quite possible to charge at much more than $20/mo/customer.

Mobile apps are great, but not a "for profit" activity for me. I'm all for doing them for fun or ad hoc, and if that takes off - great. But it seems to be a very difficult business model compared to applying similar resources elsewhere.