MT,
I think you've hit the nail on the head there. In a country the size of the US, aviation is a way of life. It takes me 2 days to drive to see my sister in Ontario, or 5 hours in my aeroplane. Drive, or fly that long in the UK and you'd fall off the edge, or run out of landing options. As a hobby it is not the cheapest, but it doesn't have the bank-balanace-busting capability that flying does in the UK.
As for the red tape issue - there's less in aviation here than there is in the UK, but still plenty to go around. And red tape in other parts of life here, there's no shortage
I think the FAA attitude to homebuilding is more of a "if you design something that will kill you, well, thats your problem", whereas the CAA's attitude "We can't let you design or fly something incase it might kill you", which is surprising in a country where litigation, insurance and suing controls virtually everthing.