Are you kidding me dude? Saying that by just doing planche push ups you will never be able to hold one is like saying that doing regular push ups will not enable you to hold a regular push up position. I would bet anything that guy would not take long at all in achieving a planche hold if he tried (if he can't already). His form may be a little sloppy, but there are many variables you can't account for (him being sore, not really trying, was already tired from doing some earlier, etc).
Please do not confuse me with saying that this exercise is better than Coach Sommers' exercises. I am saying it is another way of training. I like to alternate the frog stand stuff on some days and pseudo training on the other.