In the limit as the number of races goes to infinity, the results of selection races converges to WOC results.
While a large part of what you wrote makes sense...
I mean, technically this is the definition of an unbiased estimator. Or perhaps more precisely, converges to the distribution of WOC performances. Nuances due to terrain, the pressure, getting distracted by super amazing athletes, etc only weaken the case for strict adherence to trials races.
FYI Canadian system is not subjective for WOC but it is for JWOC.
Canada preselects WOC athletes based on previous year WOC. place in top 30 or 35 (can't remember) then get preselected for next WOC. (Louise and Emily meet that for this year). other positions are based on a win and you are in selection race in Europe.
But Canada doesn't have depth like US so when Trump wins y'all can come north and race for us (not US) eh.