I moved to San Francisco, I wanted to base my career on where the world's computing is centered. I could have stayed in the UK and always been on the periphery, but felt that since my first love was technology, rather than good beer or tea, I just moved where the action is.
I understand where you're coming from but no user should have to move country to get improved internet services. The internet is global and the services on it should be also. Did you think about staying in the UK and trying to address problems like this yourself (you would actually be better positioned to do so there)? [serious question]
If someone were going to be in SFO anyway, then this is an advantage for him.
On the other hand, for a person with significant ties to London (or other city or region in Europe) - family, career, lifestyle, whatever - it seems a bit much to move to the US because you get cheaper phone calls.
Other things being equal, I can't imagine that anyone would move from London to San Francisco because of free Gmail phone calls. (It reads like your comment is precisely about other things not being equal.)
For cases where you're calling the US (admittedly probably not too often if you live in the UK) you can use the free app Talkatone (available on both iOS and Android). It's super useful if you're an American traveling abroad: just find WiFi (or a local data SIM card) and you can call all your peepz back home.
It's annoying how many services are US-only.