Reviews don't really need 60fps, the subject is only moving a little and most of the time the camera is stationary, so there is very little movement. It would take much more space up on the servers and probably make it more of a pain to edit. I am sure if they wanted to, they could easily publish at 60fps, but few would notice the difference, so what is the point. The same reason they don't publish in 8k, nobody has an 8k monitor and few, anyone, is running 4 x 4k multimonitor setup.