It's been more than a decade now since we first saw botnets based on stealing AWS credentials and running arbitrary code on them (e.g. for crypto mining) - once an actual AI starts duplicating itself in this manner, where's the big red button that turns off every single cloud instance in the world?
Is that really "a lot of assumptions" that a piece of software can clone itself? We've been cloning and porting software from system to system for over 70 years (ENIAC was released in 1946 and some of its programs were adapted for use in EDVAC in 1951) - why would it be a problem for a "super intelligence"?
And even if it was originally designed to run on some really unique ASIC hardware, by the Church–Turing thesis it can be emulated on any other hardware. And again, if it's a "super intelligence", it should be at least as good at porting itself as human engineers have been for the three generations.
A "state of the art" system would almost by definition be running on special and expensive hardware. But I have llama3 running on my laptop, and it would have been considered state of the art less than 2 years ago.
A related point to consider is that a superintelligence should be considered a better coder than us, so the risk isn't only directly from it "copying" itself, but also from it "spawning" and spreading other, more optimized (in terms of resources utilization) software that would advance its goals.