The first cost of LED lamps is higher, possibly not as much as the supermarket prices for individual bulbs, but the longer life of LEDs must save on operating costs which might justify the higher first cost.
I'd have to wonder if 'railroad equivalent' LED replacements would be higher in percentage cost over 'domestic' equivalents due to the more restricted volume of 72v-compatible hardware for driver boards, connectors, etc. Something I would note is that the cost savings for these lights aren't the same as the 'usual' amount touted in consumer lights, as the railroads aren't paying utility rates to run them, but the much longer unattended life would be very attractive both in terms of first cost and ongoing maintenance.
I wonder whether in the absence of a parabolic reflector if the visibility from the cab improves as much as the visibility of the train from the ground.
Looking strictly at the 'beam' characteristics of the emitted light, you can get better results from a number of small diodes each with its own little aspheric reflector and lens, especially 'off-axis' from the pattern of a typical reflector headlight or sealed beam.
There's a little more to it in that the emission spectrum of most 'pseudowhite' LEDs can be relatively peaky, so that the perceived brightness of the emitted light is very high, but the actual reflected spectrum that lets you actually see things is much less, and distorted as to visible color. That's a reason why things illuminated by cell-phone screen 'white' light look so washed out and strange. There are ways around this but they're only just starting to catch on.
RME, what do you see as unsafe about LEDs as step lights?
The step lights I'm familiar with are the ones on older EMDs and cars like the Comet Is, where the light has a directed 'hood' that keeps most of the emitted light down on the steps and just the lower corner of the step risers. On the two GEs I saw, the light was larger, cushion-shaped, and shining straight out from its position in the middle top center of the second step riser, with a great deal of glare and only a small amount of 'spill' onto the step tread itself. The light itself was that fake 'warm white' that doesn't show reflected color well. I would not have wanted to gauge where the railings and step edges to climb aboard were with that light shining almost right in my eyes when standing on the ground ready to take the first step.