]It appears simple enough. Why can't it work? Something for this big of an audience never seems to.
In my experience the solutions are over engineered and under provisioned.
The over engineering tends to be vendors shoehorning in components for which they can charge handsomely but offer little relevant benefit and loads of complexity to the solution.
If you have 3 components it doesn't take long to find which one is a bottleneck. If you have 50 then it is massively harder to pin down a problem