To develop an app, even a web site is not a big deal for an experienced developer, especially if he/she can do both - front and back-end. But to launch a product in the market and make it to make money turns to be a completely different thing, which requires a different and wider skill-set than just full-stack development: idea validation with cold emails and calls, marketing, advertisement, accounting (if you are lucky), hiring (if you are even luckier).
Is it ok? Or it's just me being a greedy selfish developer?
P.S. There is a great excuse I keep saying to myself - "This is how you are learning a ton of interesting things!", and it keeps working :)