Marc Andreesen argues that being on a Mission helps bring great staff and that is a large component of success - certainly we all respond well to the idea that what we're doing is more important than just making money - I mean, we're above that, right?
However, in my experience, when someone starts a company, the question they are answering is not - what's the quickest / easiest / safest way to make money? The answer to none of these would be: create a start-up!
When you start and indeed as you grow, you need to fundamentally believe you've cracked it; that what you're doing is better and important. Is that a Mission? Maybe - but I think it's also determination, resilience and self-belief.
One thing is certain though, if a Start-up does not believe and I mean REALLY believe, they don't have a chance. And investors, employees and indeed suppliers would be quite right to keep well away.
The Machiavellian view on this is if you are the founder you actually want to pretend you have a huge ideological mission, even if you don’t. And I guess you would rather do that, than not have one, but clearly it helps enormously to have a real mission.