I feel in general people who have this thought process of "it would be cool to start my own company/site" are generally the ones that don't succeed. A business or startup should always come from a thriving problem that you, or someone else has. Or a passion for something you truly care about [if its in a competitive space]. Not having a business model from the get-go is destined for failure
Business needs should always drive the demand for new software innovation, not the other way around. Unless the "WHY" (the core issue) is specified the "HOW" (comp sci knowledge) and "WHAT" (fullstack you will be using) is pretty much pointless.
Do you have any experience starting businesses? Building businesses takes a set of skills that can be learned and practiced.
Your argument could also be turned around to say that you can’t be a successful programmer if you’re the kind of person who goes out and says “I want to build an app”
Business needs should always drive the demand for new software innovation, not the other way around. Unless the "WHY" (the core issue) is specified the "HOW" (comp sci knowledge) and "WHAT" (fullstack you will be using) is pretty much pointless.