I think the ticket prices are not helping either. Who would pay 100-200 euros to see this juve play Salernitanas and Bolognas? For the same price you can watch Milan- Juve in San Siro.
For the Salernitana game, ticket prices in the "Tribuna Est Centrale" were over €130 (fees included).
A few days before the game, a last minute sale was announced (about a €20 discount iirc), because ticket sales were atrocious (surprise!).
So
1) You have insane ticket prices (with or without the discount) that most people obviously do not want to pay.
2) People that were crazy enough to buy a ticket when they became available miss out on this discount & are "punished" because they got their tickets asap. I'm sure these people will be inclined to buy tickets again in the future.
We are now 1 day away from a crucial CL game, and there are still thousands of available tickets.