That sort of abstraction has always existed, it's just been a matter of hiring experts or labor from other humans. Reality still has a surprising amount of detail. You deal with it by engaging directly, delegating to someone else to engage with, or just brute force your way to a crooked staircase.
When you hire someone to work on the stairs for you, you /hope/ they know what they're doing, especially if you don't have the skills yourself to judge their work. Same for an agent.