Squats are not dead!
BTB, has pretty much stated my arguement, so I won't go into another long diatribe, except to say. I cannot believe that this is even a question to be debated. There is simply no other movement that brings to the table the total affect that performing squats can do. The one possible cousin to squats would have to be deadlifts.
Whether or not Olympic lifters use back squats varies. Several countries do use back squats as part of there training programs to increase strength. Several Countries primarily just do the lifts. Within Olympic lifting there is as big a divide on how to train, as there is in BB, between splits, and wholebody training.
There are various ways to perform the backsquat. Utlizing those various fashions of squats gives you a powerful tools to use in your development.
Posterier chain strength cannot be underestimated in it's importance to overall body strength. Especially in regards to standing pressing moves, which in my opinion are not given the importance they deserve. Then there is the issue of bent rowing. You simply must have good posterier chain strength to build your bent rows to a decent level of weight.
So far as I'm concerned, Mr. Boyle is smoking crack.