Yeah, this is an interesting topic. Why did Foursquare win? Was it anti-cheating provisions that were too strict in the early days? New York vs. Austin? Better PR? Simpler product? Dodgeball users as jumpstart? Who knows. One thing we do know was that it wasn't money.
I think it's pretty clear that Dennis Crowley has been thinking about this problem space for more than a decade, and foursquare is the third (fourth?) iteration on his original vision.
I presume it means that, having seen things from the inside out, his team knows winning and losing things to spend time on.
Nearly every startup ends up with a list a mile long of potential features, ideas, refinements, communities, partners and revenue sources. Being able to pick out the right few to work on (and what to say no to) is maybe the most important skill a startup CEO can have.
A founder who has been around the same space for a long time can use past experience and intuition where a newly-minted CEO knows very little and is actually best off when they recognize that.
Why do you think money wasn't a factor? Foursquare raised significantly more than Gowalla (according to Crunchbase, $71m vs $10m), and as a result grew a much larger team and presumably spent a lot more on marketing.
Actually, until mid-2010, Gowalla raised more money, earlier, than foursquare did. By then, the "check-in wars" were pretty much over.
Per Crunchbase[1][2]:
In 2008, Gowalla raised $2m, foursquare raised nothing.
In 2009, Gowalla raised $8.29m, foursquare raised $1.35m.
In 2010, Gowalla raised nothing, foursquare raised $20m. But by the time this happened (June 2010), the "check-in wars" were over (e.g., see: http://techcrunch.com/2010/07/07/foursquare-gowalla-stats/).
