[hamstercat]

You're assuming your hypothetical project is gonna work and be successful, and that dependencies breaking will be the end of it. In reality, most projects never go get that far, they go nowhere. Building successful software is a lot of work. Building the wrong thing, scope creep, not finding an audience are all much bigger problems.

That being said, just start. Build something. Make it work. Learn. You can figure out problems with dependencies going out of support when you get there.