Like most businesses Orbea is probably looking to save money if they can. May be they were get a better discount on shimano groupsets than SRAM. BMC is another brand that has mostly shimano spec'd bikes except for a few with SRAM red.

If you must have sram maybe buy a frame and build it up yourself. I usually go that route because I too prefer sram, and frames in my size usually come with smaller cranks and bars than I like. Instead of having to swap out parts on a complete bike I build it up how I want it. This could cost a little more if you don't find good deals on parts or have spare parts already, but to me its worth it.