It's ok to denying at least 15 thousands of people then.
Extra few millions more likely. Revenue would easily triple the expenditure.
Turk, I think that you have to take a few things into consideration when the plans were drawn up for the current blueprint for the stadium.
#1) THe average attendance, even pre-calciopoli was nowhere near 41000.00 per match. In fact in the last 7 years of the Delle Alpi, the attendance dropped every single year, and the attendance figures for the last two seasons, considering the quality of those two squads, were alarmingly bad. A very rapid drop just in the last 4 years of the delle alpi alone by nearly 50%. You can blame that on the stadium itself, or the fact that more people get to watch the matches on TV, but even before all of these cable/satellite providers, Juve were averaging around 47000 per match prior to 2000, so the stadium itself probably wasn't keeping as many people away as one may think.
#2) The costs of the stadium at the time versus the revenue lost at the time of calciopoli probably precluded Juve from building a bigger stadium even if they wanted to.
But again though, I harp on the first point. It's like buidling a 20 room mansion, when you are at most, going to use 10 rooms. There would be no point, and history had shown in attendance that there was really no justification at the time to build a stadium bigger than that. If the stadium can be expanded, great.