There's also survivorship bias at work here -- the SF we remember from the 1960s tends to be stuff that was initially popular and has stood the test of time. (T

There's also survivorship bias at work here -- the SF we remember from the 1960s tends to be stuff that was initially popular and has stood the test of time. (There was a lot of terrible SF in the 1960s, and it was still cluttering up the second hand bookshops when I was strip-mining them in the 1970s.)