Pragmatic Paul, or the Theologian of Tarsus?

I have just had a thought going through my head for the last few days. How many times have you heard the observation on Paul's missionary journeys that he focused on cities because it would ensure the greatest impact? I.e. that by focusing on the cultural and economic centres of his day he would ensure that many people would hear the gospel and it would then spread out to the country from the bridgeheads he had developed. Tim Keller has put this best I think when he says that 'cities are where the culture is heading' and so we ought to focus our evangelism there, following the example of Paul. Essentially the consensus is that Paul was primarily a pragmatist in his choice of cities to visit.

However, I have a tentative theory to suggest. I'm sure it is not original but surprisingly I have never heard it put forward. I think Paul may have chosen to focus on cities, and particularly the cities that he did, because they were where Diaspora Jews lived. Then as now immigrant communities lived in the cities, and Paul was committed to the doctrine of 'the Jew first and also the Greek' (e.g. Rom 1:16). His evangelism was always (I can't think of an exception) begun in the synagogue of the city and he only left there either on invitation of 'God-fearing' Gentiles or after being forcefully expelled.

I have not yet met a Christian that seems to truly believe in the doctrine so central to the early church of 'to the Jew first', and I am no different. I suspect we are not half as theological as Paul was in our thoughts on all of life, including evangelism, and without knowing it we all read in our pragmatic disposition into the bible.