the stock setup has the rocker oiling restricted/timed. if your idea has a constant supply of oil going to the heads/rockers then the mains would not have more oil
Because the oil that comes to the main bearing only has to supply the main bearing with lots of volume and the cam bearing with minimal volume and that's it . Surely you understand that Guitar Jones is showing the restriction of the cam bearings to improve oil to the main bearings.
But his method can only be applied to number 1,3, and 5 because no other provision was made to supply the rockers. The new crossover line to full time oil the rockers provides this and allows cam bearings 2 and 4 to have the same restrictions for the same reasons as number 1,3 and 5.
It is the best of both worlds if you think about it.