There are multiple grades of stainless steel, which have different proportions of metals in the alloy. The stainless steel used in the cybertruck's body panels appears to be 301 grade, which is not among the best in rust resistance, and can indeed rust depending on environmental conditions.
Given that 301 stainless is cheaper than 304 or 316, which have similar mechanical properties while having better rust resistance, I would guess that material costs resulted in choosing 301 for the cybertruck.
My metallurgy is a bit rusty (sorry), so take this with a grain of salt (which 301 does not resist well, incidentally!).
Given that 301 stainless is cheaper than 304 or 316, which have similar mechanical properties while having better rust resistance, I would guess that material costs resulted in choosing 301 for the cybertruck.
My metallurgy is a bit rusty (sorry), so take this with a grain of salt (which 301 does not resist well, incidentally!).