@BlackAmericanoNoSugar is correct. We don't get snow often enough to justify a higher level of both capital and revenue expenditure to be ready to deal with every eventuality.
On top of this, the UK climate is extremely changeable due to the Gulf Stream, with often large variations in temperature from one day to the next. We don't tend to get cold fronts that set in for weeks, as they do in mainland Europe for example.
Edited to add, there's a reason we're known for talking about the weather! It changes all the time. 😊