Yes we did spend on Pogba but we had no one else trying to compete for his signature. Real weren't completely into spending that much since they already had the likes of Kroos, Modric and Casemiro and Isco and buying a 90m Pogba for the bench would have been stupid. Secondly, there was only Chelsea that were after Lukaku and no one else. Chelsea were trying to play the waiting game hoping that Everton will drive down their price tag which led to United gazumping for Lukaku. If City or PSG were actually after them, we wouldn't have gotten them.
Even Di Maria never wanted to come to United. He was eyeing PSG the whole time but due to FFP, PSG couldn't buy anyone which is why Di Maria settled for United. Even then, there was no one who was trying for his signature. That summer, Arsenal went and bought Sanchez.
Now Mbappe for example, United enquired and were considering him but the amount of money that was thrown for him was beyond what we were planning to spend on a single player. At the end, even Real backed out of the deal leaving PSG to pay for him.