"Dennoch blieb der Betrieb möglich."
Oh my, "Betrieb" has too many meanings. I hardly remember "außer Betrieb" and "Betriebssystem". But it doesn't help so much in this lesson, sometimes trade, sometimes business, sometimes workshop. If you have some trick to make some more meanings stick to my mind, I will be thankful to you for a lot of time.
Your two first things "außer Betrieb" and "Betriebssystem". Think of a machine, In the first case it is broken, in the second case it is something which makes it possible to the machine to run. Another meaning is centred around "business" Either a firm: "Siemens ist ein Betrieb mit einem Betriebsrat." or activity "Es geht so schlecht mit dem Restaurant, es gibt viel zu wenig Betrieb." If we can say that Siemens is "Ein Betrieb", then other firms can be called so too. A blacksmith has a smithy/workshop. In a very neutral way "Betrieb" can mean "workshop" in this case. I am sure it is not complete, but that is as far as I can explain.