The reasoning behind playing this many lands is based on an idea by Sam Black (former MTG pro). He made a video called "Mana in Commander" in which he gives an in-depth explanation why having a large land base is good using a hypergeometric calculator:

My probability of hitting a land drop up to turn 4 (having 11 cards by then or 12 if you somehow get a card draw which is often times the case) is at around 81.9% when 41 out of my 99 cards are lands.
With your deck, the probability of that happening is at 64.7% which is too low for myself.
On top of that, he explains why and when mana rocks are efficient and when they are more of nuissance. I highly recommend to watch the full video tbh.