It's because we have so many different types of weather in the UK. Many other countries have long seasons of similar conditions so can afford to invest in the infrastructure to cope with it well. Norway for example expects to have a lot of snow over the whole winter period, so had the means to keep the roads clear, or Canada their airports. But to invest in the same level of equipment that might only be useful for 2-4 weeks of the whole year in the UK would not be realistic.