How exactly did Woolworth's go under, while WH Smiths is still standing?

W H Smith sell newspapers and magazines, which they sell daily in large quantities. Practically all people read them, whereas not everyone eats pick 'n' mix or have small children to buy clothes for. We are an ageing population so W H Smith will probably have more chance of surviving than Woolworths did. They will also now probably pick up Woolworths CD sales.