Let's take for example, Education. By your accounting, that should be left up to the individual states, as that's not something that should be administered by the Federal Government. In your worldview, every state can have different education standards, which would create chaos later in life -- when those students move to another state to attend college, some from, say Texas, might encounter problems when they suddenly find out that Jesus did not ride Dinosaurs and the Earth is round and not flat. And the other problem is of course that in the real world, there's only ONE set of textbooks for all states regardless of education standards, because states cannot afford custom textbooks just for them.
That explains why every time I travel to Europe, they think the earth is flat and Jesus rides dinosaurs. I guess what we really need is an international standard of education. Because however would education move forward without global agreement on teaching methods? Better hunker down and never leave your nation -- dogs and cats, living together, I tell you. Absolute chaos traveling from country to country these days.
Sorry, but your "real world" is some hyperbolic fantasy (nightmare?) that individual states will go full dark age medieval if you personally don't have an iron national grip on them, whereas reality bears out something far different. Namely, states lean more conservative/liberal on certain niche issues and otherwise behave about the same as all the other states for 90+% of life's concerns.