You are making it sound easier than it is.
If its an actual complicated problem, the parts interacts. The complexity is in the interaction.
It is also a matter of "leaky" abstractions. There is always a corner case where the abstractions isn't enough.
Business problems, like all real life problems, are hard- but in a toally different way.
You can't rollback death and not even a spoken word, and you may spend days thinking about unsolvable problems,
but the reality is normally not as rigid and fragile as the abstractions and rules of a computer system.
In real life you can bend the rules.
All tools that tries to remove complexity are fighting against the law of thermodynamics.
Or put in another way, they will make simpler problems simpler, and the rest of the problems harder.
There is probably a sweet spot somewhere around where most popular programming languages are today,
somewhere between assembler code and bpel.
It is possible that the expressability can be improved for some types of problem. It is for instance rather strange that no popular language natively can describe relations between entities, and are forcing us to work with data structures from the 60ies as a workaround for the lack of relational constructs.