Ancient Indians too: "Consciousness is all there is" (Upanishads)
From philosophical standpoint there are different variants though:
- The base reality is material and we live directly in that reality (which Musk thinks the chances are one in a billion)
- The base reality is material (or at least dualistic) but we live in a virtual reality or imagination generated by super-power AI or "biological" intelligence that itself exist in the base reality
- The base reality is a massive consciousness itself, there is no matter whatsoever (panpsychism)
Chose whichever you want to believe in. Or neither because the base reality could be something so unimaginable that we have no mental ability to understand, just like dogs, as much intelligent as they are, have no mental capacity to understand mathematics.