From an IBD editorial "Paying More Than Ever For Gas? Not If Buying Power Is Considered" by two senior fellows at Cato (see graphs above, click to enlarge):
The Bureau of Economic Analysis reveals that the percentage of personal income that Americans spend on driving has been relatively constant over time: about 10.2% since 1960.
The percentage of our personal income that we spend on fuel, however, has fluctuated a great deal more than that. When pump prices go up, people adjust by spending less on other aspects of driving, like new car purchases, automotive maintenance, new paint jobs and stereos. Over time, they'll buy more fuel-efficient cars to reduce the amount of gasoline they need to buy.
In short, consumers — not oil companies — exercise control over how much they spend to get from here to there.