I would speculate that the average life expectancy of a Morgan is way in excess of JLR and most other manufacturers?
I'm not so sure... Morgans, like many classics, tend to be pampered. Mine sits in a dehumidified garage and will probably do 7,000 miles a year - mostly in the dry. On this basis it will live for centuries.
My Range Rover has 110,000 problem free miles on the clock and lives outside 24/7 and still looks and drives like new. Would a Morgan put up with such tough love?
