This may not be true. I decided several years ago that I would consider a Prius WHEN MY CURRENT CAR IS DUE FOR REPLACEMENT!!! I only got my Prius last year. I also waited until I could afford a Prius which is are very expensive here, nearly double the price of a Corolla. It is actually better for the environment not to change cars every year or two, another reason I keep cars for many years each.
I don't fault people for their choices of vehicles. I bought a Prius because I needed to replace my old car, and the Prius was by far the best choice. However, it's not financially feasible for most people to replace their vehicles simply because they get poor gas mileage (assuming that their current vehicle is working well mechanically). Getting mad at someone for making an illogical choice 5 years ago isn't going to help anyone. What DOES make me upset is when people drive in a manner that wastes gas: speeding just to get to red lights faster, tailgating, etc. Those are choices that the drivers are making right now which hurt the environment and hur ttheir pocketbook.
Just to close the thread, I want to say I posted my initial comments with tongue in cheek. I was surprised that some responses were so serious. Bottom line, I'm loving my new Prius and the mpg (which seems to average around 47 over the 690 miles traveled). I actually treated myself to a day trip to Leavenworth, WA, today... totally unnecessary trip, just did it for fun and because I could afford the gas, ha. Say, one thing for sure... gas prices approaching $4/gal do not seem to be slowing most people down on I-90. I clipped along at the limit and was constantly being passed by huge pickups and SUV's, many towing boats, campers, etc. I swear, some of those folks had to be doing 15 - 20 mph over the limit. Hey, it's their money, I guess; but, my money is mine and most of it is still in my pocket, even after a full day's drive and a nice lunch.