This does bother me about the whole "likely we are living in the matrix" thing. If we want to design a universe that does not waste a lot of processing power we

This does bother me about the whole "likely we are living in the matrix" thing. If we want to design a universe that does not waste a lot of processing power we need to do things like have a speed of light limitation (keep it fairly slow too). But the sensible idea is to only process lazily - don't calculate till the observer observes - but it is very much like a dependency hell.