There’s sophisticated technology both in the bulb and manufacturing process of LEDs, and some of the materials used are costly (eg. aluminium is used to dispell the small amount of heat the bulbs produce).
LED bulbs are still a fairly new technology, and as with most modern advancements or inventions there’s always a bedding-in period before they become the norm. This’ll mean that they’re sold in smaller quantities and only made by a few manufacturers. The more frequently an item is made, the cheaper the production becomes due to technological advancements and new processes. In that sense, the more people buy LEDs, the cheaper they will become. There’s already evidence of this; when LEDs first came on the market they were far more expensive than they are now.
The up-front cost on LEDs is more than halogens. True. But LEDs use up to 90% less energy than halogen lamps, meaning you will often recoup your investment within just 6 months.
And the best bit is, you’ll continue saving money on your bills every month thereafter.