The second problem with LEDs is heat. LEDs produce a lot less heat than incandescents, but they also deal much worse with getting hot. Thus you need large (for

The second problem with LEDs is heat. LEDs produce a lot less heat than incandescents, but they also deal much worse with getting hot. Thus you need large (for surface area) and/or expensive (due to more expensive materials with high conductivity) heat sinks. Cheaper bulbs will tend to cheap out on this aspect, but there are also fundamental constraints especially in bulbs designed to fit traditional fittings.