It sounds all a bit overblown to me. In the end the song contest is one night and they want a venue with around 10,000 seats. I’m too lazy to count but I believe 8 UK cities have put their hat in to host it, I’m sure they will do fine. It’s not that hard, it will sell out and the TV people know what they are doing.
Its a fun habit of the media to forecast disaster for any major event, they do it by default but it almost never actually happens. There were endless articles written about how the London 2012 Olympics would be a disaster and almost everything was perfect. Games in Rio, World Cups in Brazil and South Africa, they were all fine. This will be fine. There is nothing to worry about.