I appreciate his sentiment and especially his motivation, but I'm not entirely sure everyone who is setting out to build an app must make the strict distinction

I appreciate his sentiment and especially his motivation, but I'm not entirely sure everyone who is setting out to build an app must make the strict distinction between changing the world and not changing it. This borders on being an either/or fallacy - who's to say that you can't just build something for personal enjoyment and THEN watch it grow bigger and change the world?