A block size increase is what they are looking at. And the roadmap provided by Bitmain included EVERY single scaling option. They aren't putting their eggs in any one scaling basket -- they are (appropriately) willing to explore them all.
Lightning is NOT Bitcoin. It's a financial derivative that is NOT P2P. It has points of centralization. It's cool but it is NOT Bitcoin.
Block size increase also is not the answer. At least not right now. Maybe next year or year after it will be a necessity.