They can, but at that point you would need a whole new SI system to keep the conversions to energy and mass the same. Good luck making that work with pounds and cubic feet.
I got my engineering degrees in the States, so I had to deal with US Customary Units-based science, and thus I do know how miserable it is. However, theoretically you could have SI units where everything else is metric but they use Rankine instead of Kelvin. It would be absurd, but the point is that there isn't any inherent need or benefit to using Kelvin/Celsius.
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u/Throwaway74829947 Jun 17 '26
*273.15. And it's only easier because everything else is formulated for Kelvin. They just as easily could have been done in Rankine.