True, but the whole dynamic of Test cricket is changing as Pakistan proved last week when they chased down 382 in the fourth innings to win by 7 wickets (having been 13-2). The Aussies had 180 overs available to them to grind it out in singles if they wanted too. I've seen many worse 4th day pitches than that one. Down the years, teams often started their fourth innings at the end of the 4th day or early on the 5th day on dusty cracked tracks with two spinners twirling away or seamers thriving on shooters. The batsmen's mindset was usually pure survival with little attempt at strokeplay making the play seem even more attritional.
One day very soon, a team is going to chase down 420 or whatever to win, mainly because so much more time is available to them to achieve a target.