But was that part of brilliant overarching strategy from visionary government leaders to develop and foster the world's tech hub, or an accident of history?

I think the point is that success comes from the accumulation of many factors; the best you can pull from them is a thread of attitude. "Success" is thus really an emergent phenomenon coming from a bunch of independent decisions, sometimes with feedback between them.

This is why efforts to "duplicate Silicon Valley" fail. Also why Europe was unable to move the locus of financial transactions from London even after the Euro. In both cases, there are plenty of things to point to but nobody really knows.

An accident most likely, since the policy dates to the 19th century.