I know much of UK wants to remain, and Brexit is a mess, with EU Japan-ification and inherent mismatch of fiscal policy with monetary policy b/c of sovereign states, maybe UK will ultimately come out ahead as economic free agent?
The problem with that: the EU/EFTA is a large economic and regulatory power, with which the majority of UK international trade occurs (60% of imports and 48% of exports). This is basically a consequence of both geographic and cultural proximity. The result is that UK regulatory and trade regimes will be heavily influenced by actions of the EU/EFTA market in terms of regulation and trade policy; the UK will need to remain closely aligned for the foreseeable future. This means that being "outside" that market introduces obvious inefficiencies and costs, with few indications of any economic benefits that may emerge.