One dealer I know told me they return about 50% of cars delivered for remedial work and about 1% they outright reject.
So, the factory pre-delivery inspection could be better.....perhaps.
Dealers have workshops that are busy with people that pay monies direct to them and thus help with cash flow. Warranty issues carry a flat fee and a wait for reimbursement, so there is a lot more to those statistics than the apparent poor quality returns imply.
There are also degrees of acceptability, for example some customers are far more fastidious than others and whilst I'd be quite happy to live with a blemish behind something or under the bonnet, others may not.
What should be addressed is the standard to which both aspire to. There is much room for improvement in communication between the factory and the dealer.
But where have I heard that before..?