I think it sometimes can be very quick. I think it sometimes can take a while.
Let me give you an example. In the 1970s the Japanese, for the first time, made an entry into the North American car market. That was because we had an energy crisis at the time. But what you saw was that within a few years, the Japanese car industry had something like a 40% share of the North American car market. Why was that? Why did people go out and buy these Japanese cars? Sure, to some extent I believe it was because they're more energy efficient, but also because they were better built, they had more bells and whistles on them, and frankly a lot of people thought they were cool. That change happened very quickly.
So I think with the right incentives and the right technologies, changing those aspirations can happen very fast. There are clearly a lot of things that won't, because you have embedded capital investment--for example, coal power plants and the like. But I think there's no simple answer to that.
I'm not a sociologist by training, but I think some things can happen quickly.