Sanchez and Ozil are 2 players, bought in different seasons as well, and the most paid between them was 42m for Ozil. Cazorla cost about 15m by the way, that's less than or around even with the amounts United paid for Phil Jones, Juan Mata, Rooney, Ashley Young, Carrick, Fellaini, Luke Shaw, Antonio Valencia and Marcos Rojo.
United have already spent around 75m on players this off-season alone, as well as 150m last off-season. It's not even debatable, it's easy to quantify and observe and it clearly shows United are spending far more.