You are confusing probability with difficulty; I'm pretty certain that in some sense, random read-write patterns will eventually cause it to happen with some inconceivably low probability. The question is what'd be required to find the right pattern. Will quantum mechanics put a stop to it before it propagates more than a few atoms? Is there a pattern that'd do it, but finding that pattern would break thermodynamics? Is there a pattern that could be found, but that'd require far more computing power than could ever be built in this universe utilized maximally? Maybe it's technically within reach but would require a matrochika brain. Or maybe, just maybe, almost certainly not, the kind of supercomputer the AI might get it's hands on will be able to do it.

But yea, the probability this particular strategy would be practical is extremely small. That was not my point. my point is that the rough reference class of absurdly overpowered implausibilities, when you integrate over all the myriad different things in it, ends up with a decent chunk of probability put together.