I agree with Benchy that batting conditions seemed easier in the early to mid 2000s. Why this was so? I always assumed it was a combination of flatter pitches and lesser quality of bowlers after Ambrose, Wasim-Waqar, Donald retired.
But now I am thinking along the lines of historical patterns. Before the early 70s revolution of fast bowling, there were usually just 1 or 2 great pacers in a generation. Larwood (the first great pace bowler), Lindwall-Miller, Trueman-Hall, Snow.
So perhaps the great numbers we saw in the 70s, 80s and 90s were not the normal state of affairs.
Now South Africa has definitely been a god place for fast bowling, considerably better than Australia, where the pitches have definitely flattened since the 90s, although I would be hard pressed to give an exact date for the decline.