Nowhere near the most I am sure, but for a Whirlpool dishwasher today, telescopic ball race, front cap, rear cap, pair of basket support runners, sump cover, o-ring for sump cover – 6 parts totalling £98 plus labour. A lot of money for a few bits of plastic, but includes a welcome bit of margin towards overheads.
Mine was 4 parts: on a Hotpoint washer dryer, door interlock, door handle to cure problem + mains lead and suppressor, and dryer heater to make it safe (still not sure how it didn’t trip electrics as insulation was near 0). £45 worth of parts + labour (which also included wet and dry side service).
Not that many then…
Usually replace, zero, one, or at the most two parts for a repair.