But, the thing is, many concepts can improve your mixes. It just doesn't mean that they are the only concepts that will. As mentioned, I've not observed talented mixers I've seen videos of being particularly delicate about boosts. They are often wanting to make a part just stick up in a particular range without being obtrusive, and a boost in that area may well be the best way to achieve it, whereas trying to do it by cut plus makeup gain could be a lot more abusive to the sound.
For instance, lots of people will EQ a kick drum by cutting the nasty lower mids, then bosting a desired low thump frequency and a desired high click frequency. Lots of people will pull specific frequencies out of the bass that interfere with the guitars and kick, then emphasize a particular low range and a mid-range frequency to give it definition, often where the grungy parts of the guitar have been removed. These types of combinations of cuts and boosts are very common, it seems to me.