That's a rather subjective interpretation time4chocolate. It may only be 3 businesses so far who've put their heads above the parapet, but they are three huge employers and investors in UK manufacturing. Airbus alone directly employs 14,000 people, with an additional 100,000 whose work depends on Airbus. They contribute £3.8bn a year to the UK economy. And there are other manufacturers who are still operating here, but have chosen not to launch new projects here, eg Land Rover are going to build their latest model in Slovakia.
Brexit is not about a huge, sudden shock to the economy (although if we go for the cliff-edge, it could be). It's about a gradual, irreversible decline. The economy hasn't collapsed, but it is barely growing, in contrast to the global and European economies. We were the fastest growing economy in the EU before the referendum, now we are the slowest.
City banks are not shutting up shop and moving overseas altogether, but they are quietly opening up European subsidiaries and reducing some operations here. The city will remain a financial centre, just with a smaller proportion of the work.
For the last decade or so, the UK has been increasingly reliant on inward investment to boost our GDP. That has already slowed. As a single nation, we have less to offer other countries in a trade deal than we do as part of the EU as we are a much smaller market. All we can offer is the opportunity to have fewer regulations, which will largely be a reduction in standards, which is why the only interest we've had is from the US agro-industry which has its chlorinated chicken and hormone-fed beef shut out of the EU market, or US private healthcare firms sniffing around the NHS.
The economic decline could mostly be halted if we stick within the EEA/customs union. Otherwise, the only way we can become competitive is to go for the Rees-Mogg dream of a low-regulation, Singapore style economy. And those regulations which will be eroded will be our workers' rights, food safety standards, environmental regulation etc. We are not rich in natural resources and we're too small to operate as a manufacturer outside of a regional production chain.