That's the whole point. The Nordschleife does make money. Whole the other crap that was built at the Nürburgring is what costs to much money and makes them go bankrupt.
They built a rollercoaster there. It will never be used because it has a construction error in it. Waste of money much?
They built a hotel there but all the personel in there costs way to much and there aren't enough bookings to keep it profitable.
They all did that because they would thought allot of people then would visit Nürburg but that did not happen. It's a quiet village with "just a track". And there is only allot of people because of the track. For the rest it's just a dead place wich no one would visit. They all built that with fake numbers of visitors and now they get the bill of that.
Nordschleife will never close, as will the GP circuit itself but they are in deep shit yes.
Same has been said about Circuit-Zolder... But that will never close aswell.