I can only compare what I've seen, and on that basis, I think they are.
I did GCSE Latin (I know, I know...) 2 years ago, and my teacher showed me an old O-Level text, which was far harder than anything I had to do. A girl in my class who consistently got 90-100% in GCSE practice papers could only manage a B, which would suggest it is pretty tough.
Also, I know people work hard today, but I really can't believe that people 30 years ago were all complete slackers. Working harder can't account entirely for the difference in grades achieved.