No one is taking credit, but no one is giving credit either, which is nearly the same.
Also, to your second point, when you (speaking of any regular person) put in the number of hours, it might not be valuable. When the domain expert puts in the same number of hours, it might be very valuable.
Sorry but no... theres no coorelation between value and lets call it effort over time. If a hole expert spends 10,000 hours digging a hole your left with... a hole.
If you have ever made an artwork you will know this fact in your bones.
Also, to your second point, when you (speaking of any regular person) put in the number of hours, it might not be valuable. When the domain expert puts in the same number of hours, it might be very valuable.