In a manner of words, yes.
The hair shampoo will be sold with a few pence profit per bottle. This is done because the big suppliers will make hundred of tonnes in a week so can deal with tiny margins. Car shampoo (or detailling products in general) are not the same. With low volumes and speciality uses, the margins are much much higher. In your example, the hair shampoo makes a few pence, the lusso will almost certainly be making a few pounds.
As for the technical differences... well they do exist even though 90% or more will be identical. All said, the hair shampoo is the specialised product, not the car shampoo. Sorry if it spoil any illusions, but there are no super special ingredients in car shampoos. They are variations on themes which have been with us for a great many years. Maybe one is extra concentrates, maybe another has a special smell, but the products themselves are almost never going to be 'different'. Hair shampoo... well that is a bit more specialised. Hair shampoo will be notably MORE gentle than car shampoo. Contrary to forum belief, chemical health and safety revolves around hazards to humans and we are much more prone to being damaged than paintwork (immerse your hand in water long enough and it will be 'degreased'... i should hope your wax is more resilient!). Moreover, hair shampoo will have specialised additives which bind to proteins, which soften, add gloss and strengthen... don't have much need for these (expensive) additives in car shampoo.
Now I am not suggesting people go out and buy hair shampoo for their vehicles! To be honest, if you want to clean your car on a budget, buy the washing up liquid! It is the same story as hair shampoo but does away with much of the expense due to the speciality. I have yet to see the washing up liquid which will remove wax (even when neat) and really do wonder at some of the comments I read with regards to the horrors of fairy liquid!!