> The single market and tariff free trade existed long before the EU was technically a thing. I do certainly agree about east vs west, though.

They existed long before the EU was called the EU, but that is misleading.

Both the customs union and the common market were created in 1957 with the European economic community, which got a new name and a coat of paint to become the EU in 1993. Both are fundamental parts of the European project. They would not exist without the EU and the EU would not exist without them.