This year, Bubba Watson is leading the Driving Distance stat, at about 315 yards. The 50th longest players on Tour to this point are Stewart Cink and Tommy Gainey, at 294.1 yards. The 100th longest players on Tour are Jonathan Byrd, Kevin Streelman and Boo Weekley at 288.6 yards. Spencer Levin is #150, at 281.2
In 1991, here was the breakdown:
#1: John Daly 288.9
#50: Ken Green 266.2
#100: David Sutherland 259.7
#150: Curtis Strange 255.3 (tied with Bob Tway)
So the Tour was approximately 30 yards longer all the way through.
1991 was the first year what we now know as the Travelers Championship was held at the TPC River Highlands. Billy Ray Brown won it in a playoff at -9.
Last year, Ken Duke won it in a playoff at -12. He certainly didn't consistently hit 350 yard drives en route to his victory. He was T170 in Driving Distance last year, at a shade over 275 yards.
The kicker, at least in my mind, is that TPC River Highlands is only 26 yards longer than it was in 1991, and yet while the Tour has gotten markedly longer, it yields roughly the same scores it yielded when the Tour didn't hit it so far and there was no call for the rolling back of the golf ball. Since 1991, the winning score has been 15 or more under par seven times (and three of those were pre-ProV1). I find interesting (admittedly not conclusive, but at least complicating), at the very least, as a counterpoint to the "The ball goes too far"/"The sky is falling" argument.