Yep. Prismatic cells have poorer packaging-to-material ratio (circles are optimal). They offer better thermal properties, but thermals are not the main limiting factor anymore.
And the US automakers tried prismatic cells before. Chevy Volt used them in 2012!
Chevy sells EVs with prismatic and pouch cells. I don't recall any they've widely sold that used cylinder cells. Most automakers use prismatic cells on their cars, even non-LFP variants.
Also GM had to replace batteries in 142,000 Chevy Bolts & Volts due to fire risk, so I'm not sure that should count as an example of a successful use of non-cylindrical, non-LFP batteries.
It's more complicated. You can't pack the battery at 100% anyway, because you need cooling. Cylindrical cells are also more rigid, so they need less supporting material, or they can even be a part of the support structure itself.
And the US automakers tried prismatic cells before. Chevy Volt used them in 2012!