I PERSONALLY would not do it nor recommend it.
I’m not saying that it won’t work.
If you train hard and do not exceed your capacity to recover everything will “work”. Doesn’t mean it will be optimal, but it willwork. And if doing a pathwork “program” like that is appealing to you and motivates you, go for it.
Why are coaches only using one “system”? Well they are not all doing that. Some of them are using many different training approaches in a program. BUT most of the “experts” or “elite coaches” do not use “ready-to-wear” ideologies… you won’t have a guy like Jim Wendler or John Meadows sit down when wirting their program and think “do I use GVT or GBC this week?”. It doesn’t mean that they won’t use high volume or or high density work. But when they do they build the workouts themsekves, they don’t use a system that already exist.
Furthermore most experts or coaches who have achieved a fair amount of success normally instinctively gravitate toward what 1) works great for them 2) motivates them.
Wendler is a 1A, he does better on low volume, low reps, heavy weights, not a lot of variation and the capacity to “beat the workout”. And these are the cornerstones of 5/3/1.
Meadows is a 2B and needs a huge pump, great mind-muscle connection, more volume andt training zones/technique that leads to a big lactic acid accumulation. And that’s how he trains and programs.
Furthermore, in our field most people need a “brand” to become popular/successful. Myself and Poliquin were two of the few who became successful while being generalists. When you built a brand to become successful going outside of the brand can have really negative effects: by trying to broaden your audience you can actually lose your base. An example is the old Muscle Media 2000 muscle magazine. It was the best mag 20-25 years ago. They add the best authors, cutting edge info, controversial articles (on steroids for example) but their reach was limited. When they tried to go mainstream they lost their following and didn’t gain the mainstream crowd and it dissapeared.
So coaches/experts tend to stick to what fit with their brand.