All of the above.
If I had to pick one that has slightly more influence than the others, it would be #1: advanced/expert/race skis require more R&D and more expensive materials and production techniques.
Example #1: Most technologies relevant to high-performance ski construction come from ideas born on the World Cup, and that is a very expensive testing ground. The manufacturers pay upwards of $100k annually to be a US Ski Team Pool Supplier - and that's just for the right to be able to give race skis away. Then add on wax techs and travel expenses...
Example #2: Many high performance skis use materials that are not needed in the construction of entry level skis - like wood, titanal, and Carbon fiber/kevlar. Using Titanal or other alloys add $20 to the production cost of one pair of skis.
Skier_j: Margins, in terms of percentage, aren't higher for high-performance gear. Sure, the manufacturers make more $ per pair, but it is at roughly the same percentage as a lower end ski. Quite often it is the cheap skis that have larger margins because these skis are little more than polyurethane foam, base and edges. In the US, most manufacturers clear between 30 and 35% per pair sold at wholesale. If the retailer can sell them at a decent price, they'll make about 40%. However, once April comes, the retailer will be lucky to get their money back.