Jon writes:
But, of course, Jesus preached, and Paul believed, that the world was soon to end. And it appears that many of Jesus', and Paul's, how to live teachings seem specifically tied to this belief
It seems you want to narrow the relevance of Christs teachings to this narrow timescale: the idea of a soon-to-end world. However, Christians in the main don't intepret the Bible to be teaching that to believers either then or now.
Most do not count on a coming kingdom for their immediate needs, and live each day for the benefit of the next.
The declaration for then and for now (it would appear) is that the Kingdom of God is at hand (ie: under your nose). It was access to the this kingdom-now-and-within which was intended to be the source of sustenance of man, not his forward looking to some future kingdom come. I would agree that both then and now, Christians are guilty of misdirecting their gaze. Hence the repeated exhortations about where it is we are to look.