Is Brexit impossible?

Supranational bodies reduce competition between states via coordination of taxes and regulations, allowing a general increase of both. A single currency increases the inflationary potential of all member states (less competitor currencies, less alternatives to switch to in times of crises).

Given the power this provides, is it essentially impossible to leave a body like the EU through the democratic process?

And if we were to leave, it could only ever be in name only, before joining some other international cartel (perhaps CANZUK or a worldwide ‘emergency’ assembly on climate change that remains after the problem is solved).