My problem is I can't seem to find a problem to solve that people would pay for.
Could you build similar apps but targeted at iOS or Android?
> My problem is I can't seem to find a problem to solve that people would pay for.
Hmm, there is a lot of software by lone wolf developers or very small companies that sells - and quite well in some cases. I can think of half a dozen examples off the top of my head. I had a friend who started a business writing software teaching maths to primary school kids. He wrote games with a maths learning element using PureBasic on Windows. He did very well out of it from what I remember. You could look at apps like Ulysses which has gone from a lone wolf app to a small software company and makes a lot of money. "The Journal" still sells like hotcakes but is Windows only and looks a bit long in the tooth now. You don't necessarily need to do something complete new - just different.