Sure, there is a fast-ish train link to London but Cambridge itself is quite small and there is close to nothing at all around it.
Edit: Sorry guys! Obviously many people from Cambridge here.
The problem is when you get a job at one of the surrounding companies as most of them are outside the city and once you start planning a family you tend to move out of the city as well.
Then your car is your only way to get to work basically as the city and surrounding region is not dense enough to warrant implementing good public transportation.
As for living in the city, you either have to share with someone or pay exorbitant amounts for something tiny. And what are you even getting for the money? In London you get to live in a world-class city with the best public transport in the country. What do you even get in Cambridge? It's only famous for its university, and that is off-limits for plebeians.
Flying low over waves of the North Sea, you were guaranteed to not be bothered by passengers sitting next to you because the noise of those 2 propellor engines made any conversation impossible.
(Funny enough, I took that flight for 30 minute meeting at ARM headquarters. Great trip: the night before was that famous England-Argentina games with David Beckham’s red card. Good times at the local bar!)