The difficulty of changing ingrained tradition cannot be easy, especially when they are linked to perceptions of status. But given the alternative, attitudes do have to change. Not only in Oman but also in the far east.
Why the lack of interest in woods?
I've seen old Khanjar with wooden hilts and it is after all, a renewable and sustainable resource.
With the recent massive resurgence of hard-stone carving in China and India, have you ever considered sourcing hard-stone hilts as a more 'status' alternative to resins?
They could still have partial silver covers with limited pins cemented in to connect the exterior elements, in fact following the Indo-Persian/Mughal methods of decoration they could be quite elaborate.
They would also provide a wide variety of colours and some of the stones used are extremely hard and durable.
Jade, Jadeite, Bowenite Serpentine etc.....
I bet Chinese or Indian workshops could produce a standard 'I' shaped Khanjar hilt to a very high standard at very reasonale cost!
And it's a readily available material with well rooted traditions!