I get the style this article is going for, but Cambridge Science Park (and surrounding areas) have quietly been a major hub for tech for at least the last 2-3 decades. Lots of biotech research, but Microsoft Research has been there since as long as I can remember (I went to school around the corner) as well as major offices for Intel, ARM and any other major player you can think of.

If I had to give an answer to the question 'why now?', I would say because of investment, and also Cambridge has really modernised as a city in the last few years. Plus it is a genuinely nice place to live- good schools, you can cycle and walk everywhere, and cars aren't really allowed in the city centre.