Just like a fine dinner of many very good dishes is better than only the ice cream you like the most.

Yes, but take for example companies. Companies are economic entities that resemble rational utility maximizer's much better than humans. Most companies specialize on producing one product or a narrow set of products. How can this be explained given that companies are controlled by humans for humans? It seems that adopting profit maximization leads to specialization which leads to simplistic values.

Specialisation happens to bare humans too. Much the same thing happens with many species of ant.

It seems to have more to do with living in a large community.