The differences between the Oxford & Cambridge areas over Reading & Guildford are:
- there are a lot of people with specialised careers - a PhD teaches you more and more about less and less until you know absolutely everything about absolutely nothing.
- they have an international reputation, so you get more people coming to work from other countries. I have been in meetings with a dozen people, where me and 2 others were born in the UK
With a specialised career, if you move between jobs, they are spread further apart. The last time I had to look for a job, when I had been working in Cambridge, there was one in Cambridge, another in Ongar (a 60 mile drive) and another in Oxford (I would have had to move).
If you have a partner who also has a specialised job, then its another constraint.
Some people from other countries are happy driving a RHD car, but a significant fraction are not.
At the moment, if you have a couple where one works in the Cambridge area, and one works in the Oxford area, both of them need to drive, or they need to live in London, and pay London property prices as well as paying for a season ticket.
If spending a bit on the railway between Oxford & Cambridge means that a couple can live somewhere in the middle and commute to either or both Oxford & Cambridge
East West Rail not about Professors travelling back and forth, its about extending the travel to work areas.