"The number of programmers is constantly on the rise, but many programmers no longer need to be experts, middle-skilled developers now do what needed an expert

"The number of programmers is constantly on the rise, but many programmers no longer need to be experts, middle-skilled developers now do what needed an expert before" Not really. It's more that the balance between breadth and depth has shifted. Applications are so much more complex and do so much more than they did 20 years ago. You definitely need to build a web version, and probably at least two mobile platforms too. Depending on what it is, maybe one or more desktop apps too.