I'd say it was more the other way around- your first-hand experience is limited and will inform and shape your own personal point of view of the limited area of it that you saw, compared with the more general overview of a good secondary source.
But that's just arguing semantics, really- it all depends on how informed are the secondary sources, and if it's just ill-informed opinion, then they've got to be treated with care.
For my twopenny worth, considering History again, looking through the journals and the publications, a LOT of what is published- especially in the more traditional historical fields such as political or constitutional history- comes out of Oxbridge. Looking at the author's names and institutions at the bottom of the article, "....... College" comes up a lot. Even those who're listed at other universities tend to gravitate towards Oxbridge over time, maybe starting elsewhere and then moving into the ivory towers as they become a bit more experienced and, basically, better.
I've not done much non-traditional history- of course, in areas such as African history, I suppose specialised institutions such as SOAS come into their own. For American history, certainly, the majority of the scholarship happens in America- but the principle English authorities are, generally, at Oxbridge.
Maybe I have been a little bit blinkered by this- as in, I might not notice when people aren't from Oxbridge- but I don't think that that's completely true. Lots of the more traditional historians, who are publishing in high-quality journals on traditional aspects of History, are based in Oxbridge. For example, looking at the Royal Historical Society's (
www.rhs.ac.uk annual report, of the 20 or so historians mentioned by name, at least 6 are recognisable as being from Cambridge (And I'm lucky enough that one of them is my dissertation supervisor) with a few more from Oxford.
I've just been onto Jstor and picked a few issues of traditional and non-traditional journals at random.
Articles:Oxbridge ratio Historical Journal 43.3:
9:3Past and Present No. 163:
5:1English Historical Review 116.467:
3:1 Journal of Economic History 63.3:
7:1 (All the non-Oxbridge articles are by Americans)
Economic History Review, 63.4:
4:0 (One of the articles being from LSE)
Journal of African American History 88.3:
7:0