Yes, it's unusual for an airline to hold for an hour before deciding to continue, but it has happened.
Then the airline(s) concerned must have had a very generous reserve policy if 60 minutes orbiting at FL100 still allowed a flight to continue to its destination and arrive with sufficient hold/diversion fuel.
For short haul flights in Europe, it's not uncommon for the airline to have fueled enough to undertake the trip there and back without refueling at the destination. Having orbited for an hour it may now mean that the aircraft will require fueling at destination. But this is one of the considerations that the crew and Ops will be discussing. ie which is more cost effective: burning fuel and returning to origin, then fueling another aircraft, potentially getting another crew in to get the passengers to destination, or continuing if the crew can fix the problem in the air.