Well they could, but they might get more sales and hence a larger profit if they were to offer an incentive. What is the dealer margin on these cars - £1000? Then there is the opportunity to build a relationship for future sales and servicing.dealers don't need to "earn their money" as sales are given to them on a plate, so they can just sit back and grin whilst watching the orders roll-in. 🥴
If a dealer was for instance to offer free mats and boot liner that might have a rrp of £150 but in reality only costs them £50 they might attract buyers who might otherwise go elsewhere.