Don't worry about stuff like that, you should make something that is fun for you, or something that you need yourself.
Pretty much everything I write I make for myself cause there's something I want done, and if someone else can use it too, then cool.
If you're really bothered about being successful in the `industry' though, I think this is still a good starting point. Wanna know why things like C and Linux are so successful? Cause their authors made them for themselves to use, not for someone else or a hypothetical customer to use. Things that are made with others in mind tend to be janky and inefficient, whereas things made with oneself in mind tend to be more streamlined and less complex, since if you're actually gonna be using something you would want it to do everything you want well, but nothing more.