A constant stream of bugs have driven customers away before too, so if you're waiting in the wings with a bug-free/verified version of your competitor's program, you have a real shot at stealing their customers. First mover advantage is important, but so is quality if marketed properly.
I admit personally I'm inclined to agree with coldtea. But one example where I think the stability/quality of the software really did play an important role is WhatsApp. I remember when there were a bunch of competing services, but WhatsApp was the only reliable one. As far as I can tell there was nothing else that WhatsApp did better, and yet they 'won' (at least in Holland/Europe).
Microsoft had a features-first mindset, which led to a Swiss-cheese-manifold of bugs and security flaws.
The result was that you couldn't install anything without risking a virus.
Businesses went with browser based solutions to avoid that risk.
The interesting part is, WhatsApp is built using a dynamically-typed language whose guiding principle is to "let it crash." Your code will have bugs so plan accordingly.