I would go with a little of both as well. In fact, one could argue that their site being stronger than yours played into their #1 ranking more than the older date on the article did.
It's no secret that Google wants to see fresh content on hot topics though, so showing a date after a competitor might not necessarily be a bad thing in some situations.
I've seen many instances where Google will grab any date on a page and use it as a published date. In cases where that date is old (even just 2010), it can make the article look outdated and suffer accordingly; whether that's via Google in dropping off the first page, or user with a lower CTR.
That is a bug that I'd be interested in them fixing.