How does sainsbury exist?

if you check sainsbury's annual report you'll see that they get about a revenue of 22-25 Billlon each year, these funds are put towards the growth of the business, after tax and all expenses + stock they are left with a profit off just around a billion, J Sainsbury plc is the parent company of sainsbury's Supermarkets Ltd, A business like Sainsbury's will be existing for a long time, they're the 3rd largest supermarket Chain.