very true. Some people from the second group eventually join the first one however.
oxford is an amazing place to some, and a terrible one for other.
It is amazing if you are an absolute intellectual superstar (they have a few) who couldn;t care less about being at top US places. These people in Oxford don't have to do anything, are paid well, can do as much consulting as they want, they are in rich colleges, are fellows of the econometric society, etc, etc. They could be profs anywhere, but that would entail being part of the circus. They don't like it, and prefer Oxford. The mentality is: "If you write too many papers, it means you are not thinking too much".
The place is also amazing if you are a complete intellectual dummy. In that case, you can hide how dummy you are behind the fact you can tell your grandma that you are in Oxford. These people are the worst in a way, but loving the oxford life-style is the only sensible narrative they can nurture in order to cope with their stupidity, low pay, and the fact that their best alternative would be a job at Coventry University. They pretend to be intellectuals, not to publish as in the US because they can't be bothered, etc, when - in reality - they are just not good economists.
It is easy to distinguish btw these two sets of people because the publications of top journals is highly bi-modal: in the former group, almost everything they write is indeed very good (when they dare to write or finish it). In the second group, they absolutely have written NOTHING of worth.
The problem with Oxford is that the former group is older and have no interest in making the place better. In fact, they also realize that the place has become so bad that they just can't hire any junior remotely close to their level. so they might just as well given up.
The place is horrible for the third group: people that are actually good and active economists, understand that there is value in building an active group, being surrounded by well trained phds, nurturing assistant profs, etc. That is, people that are not Nobel Prize winners, but that can (and) do very good work and are passionate about econ. These people of course have outside options and - as soon as they realize how oxford is - leave.
The list of the third group is incredibly long and ALL those currently in the third group are looking to move. There is not a single exception to that.