Your post got me interested, so I watched the Crane run from 1966 and the video of the 2009 world championship finals between Immonen and Cohen, won by Cohen 200 - 181. I only looked at the first 150 balls from Immonen and Cohen to compare to Crane's 150.
Crane pocketed eleven balls up table, mostly as a result of two racks where he broke the balls open from behind the rack. He let the cue ball get up table only one time on a break shot.
Immonen pocketed thirteen balls up table and had one behind the rack break shot but sent the cue ball up table four times on break shots, one of which was costly because he missed the next shot and ended a run.
Cohen pocketed nineteen balls up table due to five behind the rack break shots and he sent the cue ball up table twice on a break shot. Cohen missed on one of his behind the rack break shots and ended a run. Cohen seems to have more of an old time game, perhaps due to his mentoring from DiLiberto.
Based upon this I would say the number of balls pocketed up table are directly related to the number of behind the rack break shots which tend to drive more balls up table, but it is still mostly a four pocket game.
On the modern equipment it seems like the balls break open easier and it seems like some of today's players aren't bothered by sending the cue ball up table on break shots. I think back in 1966 you risked getting called before the board to explain your actions if you sent the cue ball up table four times like Immonen did.
You're probably sorry you asked, but there it is.
Maybe the nap cloth isn't that slow then... Idk. I wonder if there is a table around set up exactly like they were 40 years ago.