First of how dreams "really work" varies greatly from person to person.
You mean there are people in the world who never have dreams where physically impossible things happen? Every dream they've ever had in their lives adheres strictly to the mundane logic of real life?
I think the general rules of the game for real-world dreams are
the same from one human to another. If this is not true, please link to the scientific studies that show that. This would be rather startling info and I would think it would be well known. There might be a few random cases of people whose dreams never deviate from the rules of the real world, but they would be bizarre psychological outliers.
Unlike you, I don't see any reason to give credence to the arbitrary rules Nolan pulled out of his ass for this movie. They were obviously cobbled together for one purpose: to create a summer blockbuster movie with the familiar attributes - car chases, video-game type "levels", explosions, etc - that would please the average movie watcher and not challenge or scare them too profoundly.
It was an okay flick but not nearly worth all the fanboy drooling on the internet.
The artificial mechanisms behind it are too glaringly obvious. It reminds me of The Matrix
- a lot of faux profundity mistaken for the real deal.