This was my fear about app and game ideas. Then I realized how much work is involved to make something polished. Now my preference is to put ideas out there in the hope someone else will do it.

Usually even without sharing someone with the same desire has done it within a year or two. Two of my recent projects started when I thought no one would do it. Then years later there were others, and they were free and open source.

Lesson learned. Spread the idea and let others do the heavy lifting. Only do it yourself if you're bored or very passionate.