That is standard for most reality TV work. I watch quite a lot of similar stuff on you tube, and it gets pretty boring if you show the whole 27 hours of sanding spraying and polishing, so they just present the finished result., Its also pretty clear that the 'presenters'; often come in and do one little bit, and there must be a whole army of mechanics or whatever doing the rest between the episodes.
There are some more genuine and honest 'repair' channels on You Tube that are more interesting for mature audiences with a brain.
I like Diagnose Dan, because he admits ' I fixed the problem already, but this is how I diagnosed it' so he puts it back the way it was and walks you through it. Less reality TV than educational.
Similar with 'Rainman Rays Repairs'. Its funny, its real but its also a step by step instruction on how to fix cars the real way. Like 'Ok Ive edited out the last 7 tries, and this is the final attempt to get the preload right'.
The lesson is, that there are infinitely better programs on YouTube than on the telly, these days.
If there is nothing on telly, I just fire up You yube. My TV is viewed on a laptop or desktop anyway, via the magic of a tvheadend server.