FP64 is not that precise; proper simulations usually need much higher precision. Even ancient Intel could do 80-bit FP.

This very much depends on the simulation. CFD historically used 64-bit, with extended precision used internal to an extremely small number of poorly conditioned operations, or with very stiff equations; today it's not at all unusual to use single precision or (strategically) mixed precision, depending on the problem. I think the strongest statement you could make about simulation workloads, rather than them "needing" a specific precision, is that they are usually properly analyzed to determine the needed precision, and then run at that precision.

	▲	storus 14 minutes ago \| parent [-]
		One could argue that the interesting parts of simulation require higher precision. When you are in stable conditions, that's where your intuition might be sufficient already; once you hit those ugly parts then you start requiring as high precision as you can get to have any correlation with reality. Even a simple solar system simulation through gravity interactions has significant drifts in FP64.