If you imagine elves as having a lower TL than others, I would think you would pretty much have a choice of one or more of the following:
- They can't have it
- They don't want it
- They don't need it
Historically, "cold iron" was believed to be harmful to or to repel beings such as fairies (which were often considered the same as elves). In
GURPS terms, this could be covered by variations of things like Dread, Revulsion, Weakness, possibly Susceptible depending on the setting.
One of these and Vulnerability to iron could be a justification for elven society forbidding or at least strongly discouraging its use.
And there are sometimes low tech ways of dealing with things that work just as well as higher tech. For example, I live in the country, and keep ants out of the house and snakes and wild animals away from my front door by using methods that could be done at TL 2 and below.
And there can be the issue of, "If I can take care of it with a few words and a wave of my hand, why would I want your machine?"