If you consider cross training to be 30 min on the elliptical then hitting up the machine circuits and then maybe doing some bosu ball situps, I totally agree with you.
On the other hand, you have programs like crossfit which are not specialized, but can turn people into what I consider to be athletic freaks. It might not be the best approach for someone trying to squat 700+ lbs, but for general athleticism, I think it is a good training program. I was looking at the website for the crossfit games the other day, and was pretty blown away with some of the competitors.
In fact, I would recommend some of the more intense cross training programs to some of the guys I see in the gym who are really into upper body specialization. They look great, until you look at their legs and then are like you have got to be kidding me. I would even recommend these programs to the guys specializing in squat rack curls supersetted with dumbbell pullovers.
If you are an advanced athelete you would probably stick to practicing your sport.
If you are currently not practicing a sport, I think a broad and varied training stimulus, including me and de lifts, hiit in the form of sprints, bw, or barbell circuits, with work on some of the olympic lifts to be a pretty good strategy for getting stronger, faster, tougher, etc. It might not be cross-training, but it is in my opinion a perfectly acceptable approach to training.
I haven’t really paid attention to the Crossfit “phenomenon” although I’m aware of its presence in the industry.
I know that they’re really into the “functional” stuff. However, that doesn’t imply they are cross-training. It’s entirely possible to specialize in functional training only, and if you do it, you will surely become very good at it after a while.
I have other problems with functional training, but at least it is a more-or-less specialized training modality (or can be).
Personally, I am not impressed by “strong” people who look either skinny or fat. I’m an aesthetics guy. That’s my personal bias. And I think the majority of people out there could do with improving their physical appearance before they improve their squat or deadlift numbers.
I do not buy into the mentality that “the fastest way to improve your appearance is to get better at the deadlift” or some such exercise. My inclination is to put people on a bodybuilding-style hypertrophy routine if they are more concerned with appearance improvements than performance.
Higher level competitors (weightlifters or piano players) always get there through tons of practice and specialization.
You look at how pro bodybuilders train - that is the OPTIMAL training method for hypertrophy. Anybody who claims that “it’s all drugs” and you’re better off training like a powerlifter or hopping around on a ball is either clueless or lying through their teeth.