Timothy Carney offers a clear example at The Washington Examiner:
The 2007 Energy Bill, a stew of regulations and subsidies, set mandatory efficiency standards for most light bulbs. Any bulbs that couldn't produce a given brightness at the specified energy input would be illegal. That meant the 25-cent bulbs most Americans used in nearly every socket of their home would be outlawed.
People often assume green regulations like this represent the triumph of environmental activists trying to save the plant. That’s rarely the case, and it wasn't here. Light bulb manufacturers whole-heartedly supported the efficiency standards. General Electric, Sylvania and Philips — the three companies that dominated the bulb industry — all backed the 2007 rule, while opposing proposals to explicitly outlaw incandescent technology (thus leaving the door open for high-efficiency incandescents).
Competitive markets with low costs of entry have a characteristic that consumers love and businesses lament: very low profit margins. GE, Philips and Sylvania dominated the U.S. market in incandescents, but they couldn’t convert that dominance into price hikes. Because of light bulb’s low material and manufacturing costs, any big climb in prices would have invited new competitors to undercut the giants — and that new competitor would probably have won a distribution deal with Wal-Mart.
So, simply the threat of competition kept profit margins low on the traditional light bulb — that's the magic of capitalism. GE and Sylvania searched for higher profits by improving the bulb — think of the GE Soft White bulb. These companies, with their giant research budgets, made advances with halogen, LED and fluorescent technologies, and even high-efficiency incandescents. They sold these bulbs at a much higher prices — but they couldn’t get many customers to buy them for those high prices. That's the hard part about capitalism — consumers, not manufacturers, get to demand what something is worth.
Capitalism ruining their party, the bulb-makers turned to government. Philips teamed up with NRDC. GE leaned on its huge lobbying army — the largest in the nation — and soon they were able to ban the low-profit-margin bulbs.