No such term as “shampoo” is in current use in commercial cleaning.
Generally, old time carpet “shampoos” were detergents.
We use both detergents and solvents.
Solvents are volatile and evaporate – so if you don’t extract them completely – no harm.
Detergents must be thoroughly extracted to remove all residue as the residue will hold any dirt that gets tracked on afterwards – “resoiling ” – the carpet.
Your daily vacuum cleaning won’t break this bond so the dirt will stay in the carpet with the chemical and you will have defeated the purpose of cleaning the carpet in the first place.