Mad Jock has it about right, in my opinion. Oxford is a good school, without a doubt, but it has very large overheads and is thus more expensive than schools with lower costs. Like any aviation-related school, Oxford has to make some hay while the sun shines because income is hard to get when the market goes through the low point of its cycle, as it always does - and, thanks to its airfield, buildings, and high staff levels, Oxford is not well placed to strip out costs when the market turns against it. Add to that the 'brand factor', and you can see how Oxford justifies (and needs) its high charges.
WWW makes an interesting point about the links between advertising and magazines, and one which is probably highly pertinent in the somewhat limited market of aviation training (though, as a long-time '
Car' subscriber, I could argue the facts about Porsche's advertising

).
As w always say, don't believe
any marketing hype; do your own research and go for the FTO that best suits your requirements and budget.
Scroggs