Maybe it was once, but things like Myfitnesspal make diet tracking pretty easy for everyone nowadays. As for timing and macronutrient composition of foods, that's something the dieticians can probably help, but it's also something you can learn in a few hours by watching Youtube.

Having trainers, dieticians, etc. professionals around you to help with everything probably makes it easier in the sense that you probably save one or two hours of planning and organizing your life per week, and probably your programming is a bit more optimized, but it's hardly a game changer. If you are somewhat devoted to the topic, you can learn and do all the same stuff yourself.

Yeah, it's literally paying someone to follow you around all day and control what you put in your mouth. There's no guy in spandex telling me not to buy those Reese's Pieces at 7/11 when I'm bored on a Sunday.