Given that past coders for the NYTimes have included the creator of CoffeScript/Backbone and the current maintainer of ClojureScript/Om, it seems (at least anecdotally) that whomever is in charge of staffing the dev team is doing a decent job.
Of course, some of the worst technical debt I've had to deal with came from "world-class developers", so this is no guarantee that they won't collapse under the weight of their own code at some point...but I think the odds are at least in their favor.
I guess the underlying question is how they plan to support these web technologies into the future; what's their long-term technical debt in that sense?