Building a library or app that becomes popular and successful isn't just about effort or will power. You need to have the right idea at the right time (and know it), you need suitable distribution channels and you probably need a big network of fans/followers to get it off the ground. Plus it has to be unique or novel enough that there isn't a good competitor already on the market.
It's like becoming a TV or movie star – millions will dream about it, but it'll only really happen for a tiny number of people. Many completely suitable people won't get it because they weren't in the right place / right time.
Simply put: many many factors have to go right for you to get a library or app launched and a significant audience actually using it.
Compare that to getting a job or pleasing your client or learning a new skill. Those things are way easier and way more likely to occur.
So while it's good to keep an eye out for opportunities in open-source or entrepreneurship, you shouldn't be beating yourself up over not being able to find one.
Instead, put your time and energy into SMART goals:
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