The social factors are still present, because humans are still essentially the same beasts we were 50 years ago.
The technical examples are almost completely obsolete, and only make sense when you think about the 0.034 MIPS System/360 of 1964. When you've only got 8 KB of memory, suggesting that the user should be responsible for handling leap years, instead of wasting 26 bytes of system memory (as Brooks did) made sense, but today it seems downright silly. I don't know any system that small today -- your telephone is thousands of times more powerful than the most powerful OS/360 system. Today we know a lot more about usability and human-computer interaction, and making the user responsible for that category of thing is just crazy.
