There's really no buying an airplane in the US to beat traffic, but then a typical commute or trip in a light airplane in the US would have crossed the UK several times. Expense is relative.
Years ago my first student came from Germany. He flew to the US, we managed to get him through his private pilot certificate in 30 days, and then he rented an airplane and toured around the country with his girlfriend. He included the cost of flying her over, and both of them flying home, in the total expenses, and it was still less than he would have spent just to get the private, in Germany (or the UK, I suspect).
It's relative, none the less. Prices are five times now what they were twenty years ago, and were I to start flying today, I could never afford it.
A typical commute to go see my children is a ten hour drive. (only about four hundred miles direct, but I have to drive around the Grand Canyon to get there). Flying would be faster, but I can't afford it. I can't afford to rent an airplane to take my kids for a flight, certainly not to own an airplane. I fly for a living, largely because I could never have afforded, and still can't afford, an airplane. In fact, that was originally my purpose in flight instructing; I couldn't afford to fly any more, and I wanted to be able to keep flying.
So far as subsidized airports and flying...communities are responsible for their own expenses. If a town wants an airport, they build an airport. However, airports don't get built here. Existing ones are maintained, or more and more, destroyed. Most airports can be traced back 60 years or more, and they disappear each year. The federal government does match or contribute some funds to some improvements, but most of what goes into an airport comes locally. It's made up in transient fees, landing fees, tie down fees, fuel flowage fees, hangar rentals, and taxes.
Wide open spaces is relative, too. In the Eastern US, it's very crowded, with a lot of airspace issues. In the central and western US, you can fly for hours and never talk to a soul or see a runway or airport. Much of the airspace in the west is uncontrolled (though a lot of it is defense airspace, too).
The issue is much bigger, of course; it goes back to the basic economic structure for the country and the political climate. The US doesn't have nearly the tax that the UK or much of Europe does; the government doesn't provide as much, and the burden is more on the individual. In the case of funding, it's a hot topic right now, with a big political battle being fought regarding user fees. Nobody here wants to see the airspace of the cost structure turned into another europe, any more than anybody really wants handgun control, socialized medicine, or anything else we perceive as threats to freedom.
The airspace and the cost structure here just hasn't been messed up yet. Give it time. It will.
Over the past few years, a gradual change has taken place in everything from weather reporting in the US to airspace, to align it with the european model. Most who have watched this change from the US would probably agree that it's going the wrong direction...it's not the system here that's a mess.