It's always hard to define exactly what is an idea; and much that is obvious to us now wasn't at that time - which means that we add interpretations; especially when the stories are allegories.
Plato's cave is more that many don't see the true world, only a dim glimpse or shadow of it - not that we see something completely different from reality.
Cartesius is that what we see has nothing to do with reality; and that some external agent is doing that.
There are probably many others with ideas, that we could interpret as something similar as simulation - the question is whether it was intended as that.