You make a lot more money than that. He will be earning more from youtube alone.
Then factor in sponsorship money, referral money, merchandise profits etc.
Plus I am sure a lot of his modifications he did not not pay for or certainly not full ticket price as a deal would have being made on the basis he was advertising for them. I've had done stuff for cars free or heavily discounted due to posting on forums, instagram etc. which for me is far less time consuming than making youtube videos.
The work and effort that goes into making youtube videos, editing them is really serious, I know first hand as its what my girlfriend does and she works damn hard and generally can produce 3-4 videos a month, or maybe 4-5 videos if she literally just works 7 days a week, so its not an easy life for them and end of the day if people are viewing, giving a thumbs up they are providing a service by entertaining people.