RCB beat me to one part of my rebuttal. I am with him.
On the rest, as best as i understood Elon Musk's point, he's talking about a variant of the holographic universe. I am firmly behind him with SpaceX .. not at all with the whole "Matrix" vibe.
Seriously smart people have postulated that. My feeble mind doesn't buy it though. It has the problem of another analogy. IF we are IN the simulation, HOW do we know that? And why is the "creator" hiding from us?
Ask a fish about the water he swims in, and (if he even understood you or some other fish who could "talk") he'd say "what water"? Here, Fish, take the "red pill" and wake the heck up!
My mind is open to all ideas .. but I am more in the "Unified Field" camp (John Hagelin, Henry Stapp, et. al). And, to be fair, there are people that think Hagelin, Stapp, et. al, are full of sh*t.
Therefore, by the transitive property, so I may be full of sh*t too.
This picture -- complicated and I only understand it superficially after "Level 4". The top is the world you can see. Move down to smaller and smaller things .. its murky, but that's where I think the answers are.
We just aint smart enough .. yet. but a scant 200 years ago, we didnt understand hardly ANYTHING on this chart.
Get all the way to the bottom of this chart, assuming we get through "supersymetry", a TALL order, and 99.9% of the mysteries of THIS Universe are answered.
The Universe next door? Says very little about that one, OR the infinite others that "likely" exist.