Didn't see it mentioned in other comments, but a particular failing of LED lamps is their unsuitability for critical color matching applications. Fluorescents

Didn't see it mentioned in other comments, but a particular failing of LED lamps is their unsuitability for critical color matching applications. Fluorescents and CFLs are available for that use, but to date haven't seen LEDs that are satisfactory. This is important in art studios, museums and other venues. For many years I've used specialized 48" T12 fluorescents with good results. Incandescent/halogen lamps are also essential because color selection can depend on the target environment, there's a world of difference between indoor illumination and daylight in this respect. The high-efficiency lamps described in the article will likely be very useful and a welcome refresh of a light source that's so far been hard to emulate with LEDs. With IR energy being pumped back into the filament, maybe it's an option to run a hotter filament emitting a higher color temperature. More likely the input energy is just decreased so the resulting filament temp remains in conventional range. There still might be an issue re: time to filament burnout not differing from conventional lamps unless the filament is modified in some way. In the long run I imagine LEDs will be improved, curbing the disproportionate blue output, while enhancing and smoothing the long end of the spectrum. LED dominance will probably be complete when color rendering is optimized, they work properly with electronic dimmer switches, and lamp envelopes produce illumination as diffuse as classic sources, e.g., like "frosted" incandescents.