I don't generally support socialism, but your statement is completely wrong. What about Scandinavia and Germany? What about worker's rights? The US itself has plenty of measures which were deemed socialist years ago[1] but are now so common that we take them for granted.

[1] Note that socialism designates a vast array of different ideologies and its meaning is continually evolving. It certainly did not mean the same thing in Steinbeck's time as it does today.

Edit: grammar