Yes, data companies know a lot about us. They even have wonderful analyses and a Z report about us thanks to their artificial intelligence applications. They can offer findings and recommendations that a psychologist cannot.
I don't like to compare myself to others. However, I can make a comparison in case of injustice.
Far, far more than most people realise. And they are using it effectively.
I was saying to my wife the other day about gym workouts for different body types. The best way to design a workout, is find someone with a similar body type and the type of body you want to achieve, and do what they do :)