Yep, they do have a different mindset. Of course, having that different mindset won't guarantee you'll be successful as nothing is guaranteed, depending on your health, background, etc., but mindset is what will drive forward one person whereas someone else with the same circumstances etc won't be successful without the mindset.
I see it with my clients. I've got so many clients with virtually identical backgrounds, skills, qualifications, etc., but they just don't compare in terms of what they achieve, i.e. two qualified self employed electricians. One just oozes enthusiasm, innovation, "go getting attitude" etc and has massively grown his business, employing others, etc. The other, despite similar background, qualifications, etc., is really "woe is me" - everything is wrong, he hates his customers, he's constantly feeling ripped off by suppliers, gets fined for late VAT returns (of course HMRC's fault), and is barely earning more than an average wage, whinging customers don't pay his bills, etc (I'm not surprised as he's probably crap at his job and probably doesn't turn up on time - he doesn't give any vibes that he cares about anything!). Same qualification, different mindset, different outcome!