I guess you could get some from a non bike specific shop a but cheaper maybe.
probably generic bearings which will be substantially cheaper from a bearing supplier (from memory our Fulcrum R7s take the same 6902 bearing as Hope and a bazillion other hubs so looks like Fulcrum use standard not unique bearings). When Fulcrum use the suffix ‘CX’ on wheels they just have double-sealed bearings, whereas as the road ones only have single-sealed to reduce rolling resistance.
I’d google the bearing type and buy them off ebay or a bearing supplier and fit them myself rather than buy new wheels (unless you want to use it as an opportunity to uprade, in which case what’s your budget?).
If they were sold as “for CX” and you’ve used them a handful of times, take them back and don’t take no for an answer, they should replace them.
not a chance that’s gonna happen:
1) it’s planet X
2) wear and tear.
You can’t define what is reasonable wear as it’s down to how it’s been used and maintained. I had to replace EVERY bearing bar the pedals on my CX race bike (3 months of doing only 10-15 miles a week) as it was being used in crap conditions and then repeatedly power-washed.