Been in an airplane...
No one wants to waste time at a major event checking/returning motors to spec. If you want to know why... Ask anyone who went to the 2018 carpet nats. So much wonderful track time was totally wasted ....
if I had my way every Can-Am race would be pure handout with daily motor return and random re-draw of motor the next day.
The price of things will vary from your club track to a major event like the HC. Using new motors for every event frankly just generates unnecessary cost. We've put 100ks of laps on motors without noticable degrade... And this was without any proactive work (which won't be the case for major event motor rentals --- manufacturer will check/recheck)