Reality being a simulation, which has to be one of the most lame conspiracy theories I've ever heard. When you reach a point where a simulation is so complicated that its indistinguishable from reality, you start to lose any kind of focus on what a "simulation" even is. If this simulation is so complex and precise that it can simulate things like molecules and atoms at a universal (or least observably universal) scale, this you're dealing with something that's more like an artificial universe. Which has its own set of philosophical ramifications, but one is ultimately forced to question what all of that effort is really going towards and why anything would bother with it in the first place.
Well, we have The Sims 4 and have been constantly running all sorts of simulations for financial, technological, environmental etc. reasons ever since the first computers.
Something telling about the lack of imagination for this theory is that its proponents never really detail what the actual reality is or looks like.
There's no reason why someone believing we're in a simulation would have any knowledge on what the "actual reality" outside it looks like. One doesn't follow from the other.
A civilization/entity with the sheer amount of technical capability and processing power to simulate whole universes would be so far beyond out current understanding that the "real" world would have to be totally alien. Even if you could somehow do the impossible and defy your programming like in the Matrix, how are you supposed to interact with the real world you don't even know the first thing about?
That is pretty much the point of the simulation hypothesis. The idea is roughly speaking that given our current technological advancement and speed of growth, it's reasonable to assume that we could possibly at some point down the line reach a state with computers powerful enough to simulate reality (at least to the fidelity we're familiar with ourselves). Not right now, not at a specific date, at some point, it's theoretically possible.
If this point of creating simulated universes or realities is ever reached by any civilization (not just ours), there would be an exponential increase in the amount of realities. You would go from one, to a thousand, to a million, to a billion, to who knows how high? How many computers do we already have on earth, and we're nowhere near that technological stage? So either:
A. No civilization has ever reached that state of technological advancement
B. Some civilization has reached that state of technological advancement, and we're in the same original universe as them (odds are 1:1,000,000,000+)
C. Some civilization has reached that state of technological advancement, and we're in one of the simulations (odds are 999,999,999:1,00,000,000)
And obviously if we leave the door open for the possibility of living in a simulated reality, we would have no clue about the age of the universe. Our universe is estimated to be 14 billion years old. Is that the age of the universe or just the age of our "save file"? If we assume that it's merely possible (not that necessarily true) that we're in a simulation, the real universe around us could've been going on for trillions of gazillions of years. Technically even if we're in the original universe it could've, we don't know what preceded the big bang. So what are the odds someone created a supercomputer powerful enough in that timespan, if we got this far with computers when life on earth has only existed for about 10 million years?
I'm not saying I believe it or that it isn't lame, I just don't think you fully explained the theory. It's really more of a philosophical question than anything that has real world consequences. Even if reality is a simulation then so what? It's the only reality we know. Knowing about the simulation doesn't give you the means to escape it. Doesn't mean it isn't a simulation, though.