- phone holder in wrong location or not securely fastened
- missing first aid kit
- split in windshield wiper
- low washer fluid
- headlight alignment
- tyre slits from curbing
- tyre wear levels
- surface dirt on brake lines
- rock chip in windshield
- rust on brake disc
- bodywork damage
I think it is reasonably safe to assume that the issues that are not directly related to the specific model of the car are roughly evenly distributed among cars of the same age.
No, because most cars are tested after a yearly servicing which includes a pre-inspection and remediation of issues. Tesla is somewhat unique in not having dealers and a recommended yearly servicing schedule.
There is an impression in the comments and the article headline that the test is about vehicle reliability. I'm pointing out a small list of the non-reliability parts of the test.