I’ve asked for a purchase price at the end of every lease, purely out of interest, and every single time the price they want has been thousands more than it should be. They get away with it sometimes because people have a fear of buying second hand cars and take the view that they know the car so aren’t buying a lemon.
The problem is that the car comes with no warranty (and, Sod’s Law dictates that something major will go wrong in the year after you buy it!). If you buy from a dealer, you will have a warranty, any servicing or tyre requirements will have been addressed prior to sale and, for those that need it, finance can be arranged. Also, nobody in their right mind pays the screen price. A discount can always be negotiated, something you cannot do with Motability!