Correct me if I am wrong, but I believe what you are asking is that if the pros started with an open break shot, what would their average runs be?
I practice this way often, and most of my runs are in the 28-42 range, sometimes I go fruther than that, sometimes I can't get out of the first rack.
I would guess that Schmidt and Harriman would be in the 56-70 range, and would tell you the same thing about the days that they can't get out of the first rack.
It depends on the equipment, and I have always maintained that the DCC numbers are not representative of what you would find in the every day numbers because of the Diamond table. If you want to see big numbers, get a Gabriel, Gold Crown, or an Olhausen. You won't see a lot of big numbers on a Diamond because of the pocket cut on those corner pockets. I don't know how far Ervolino would have gotten with those big angle break shots playing on a Diamond table.
The Miz said, "On these tables, you need to get right every time. If you don't, you're sitting down because the ball won't go."
Danny's 139 in 2006 is an amazing number of balls to run on a table with pockets that tight, as is John Schmidt's 112 the same year.
By this, I am saying that the equipment is a big part of it. Personally, I hate it when the balls are waxed. For me, freshly cleaned/waxed/slick balls on Simonis 860 is a skidfest (I know that Danny Harriman feels the same exact way) whereas this does not bother John Schmidt in the slightest.
Another thing to note is that nobody gets up and runs 100's consistently. I play 14.1 almost every day for 2-3 hours. Some days I go home with high run for the day of 28. Some days I get above 100, some days I get into the 120's (not too often). It all depends on how well the balls are spreading and how well I am picking them off in the correct patterns. Some days are better than others.