Some would trace it back to VT's entry into the ACC as being the inflection point, others pick later years. There's always been a few really, truly tough-as-nails players on every VT team (probably true of almost every D1 team out there), but the top-to-bottom level of it you saw in the mid to late 90s is gone. Changes in rules and in the predominant way the game is played don't explain 100% of the delta.