Yes, but you can't just inject 100s of megawatts into the middle and hope it magically gets to the coasts. There are a lot of losses on the transmission lines and each step has a max capacity.
Sure, it's not a trivial exercise, but neither is food transport. That's a much harder problem that's been solved because we had to. The main reason we don't have a continental grid is because we don't need one.
Talking about losses is a sign of ignorance. Generally a comment making that point can be ignored. Losses are a point that people repeat: maybe because it "makes sense".
Other constraints are what matter - especially if any links are close to their capacity.IAAEE