It has been that way since Unix V4 which released in 1973. Back then moving to something that breaks after 65 years was a massive upgrade over the old format th

It has been that way since Unix V4 which released in 1973. Back then moving to something that breaks after 65 years was a massive upgrade over the old format that wrapped after two and a half years. And at least from the standpoint of Unix engineers 32 bits was more than enough: Nobody is using Unix V4 in production in 2024, never mind 2038. Why it made it into Posix and wasn't updated is a different question that's a bit more difficult to answer