just because you would only use a fixed for riding across town doesn't mean everyone does. I ride 100+ miles at a time on fixed, I can be stranded in middle of nowhere doing either. I know how to maintain a bike and check for wear and so would start to carry spare chain hundreds of miles before the old one broke. The sprocket being rohloff only is far more likely to be irreplaceable than a 1/8 chain which isn't overly uncommon.
just because you would only use a fixed for riding across town doesn't mean everyone does. I ride 100+ miles at a time on fixed, I can be stranded in middle of nowhere doing either. I know how to maintain a bike and check for wear and so would start to carry spare chain hundreds of miles before the old one broke. The sprocket being rohloff only is far more likely to be irreplaceable than a 1/8 chain which isn't overly uncommon.