Endowment and Foundation return objective

With endowments and foundations, when they ask for return objective it is usually: = (1+spending rate)(1+management fees)(1+inflation) -1 Since we are looking at current year return, why is inflation already in there? Next year i understand that inflation is a factor, but now at time 0, inflation hasn’t yet occured, so why is it there.

This retrun is for perpetuity not just for a year.