Stubhub isn't the villain here. The company only takes a percentage of the seller's asking price. The real villain is the person who got the tickets ahead of everyone else. Whoever has the tickets can ask any price they want. It's up to the buyers to refrain from paying those obscene prices.
If no one buys, then the prices will fall.
The week leading up to the show you can probably get those same seats for $200-$300 or so each if they're still for sale. I really don't see why someone would pay $5,000 per ticket and I don't understand how the ticket seller thinks they could get that much for it? I guess some folks are willing to pay that much otherwise I don't think the sellers would be asking for that kind of money.