in the absence of any of them being able to give a single tangible example of how their life is going to be better after Brexit
I would say that the people in the North of England have had their voices heard for a start - Boris Johnson held a cabinet meeting in Sunderland last week.
A lot of people think their wages have been suppressed by immigration - e.g. construction workers and pharmacists.
trade with the US instead of the EU, at whatever cost to the environment
The Dover-Calais problem has prompted many companies to rethink their supply routes - importing goods by ship to ports around the country should be better for the environment than trucks driving up and down the motorway.
The cost of food should come down - e.g. we can buy cheaper virgin olive oil from Morocco. Also, for example - Eswatini/Swaziland has a well established canning industry supplying Europe with tinned fruit. Eswatini also grows peaches which they can't sell to the EU because of EU tariffs - it is cheaper for Eswatini to import peaches from the EU, can them and then export them back to the EU.That's not good for the environment.
Voters like me don't want to be part of a Federal Europe - several of our prominent politicians do want this;
"The European Movement UK is an independent all-party pressure group in the United Kingdom which campaigns in support of greater European integration and for reform of the European Union.It is part of the European Movement International which pushes for a "democratic, federal, enlarged European Union".
"The President was Lord Paddy Ashdown until his death in December 2018. Former Deputy Prime Minister Michael Heseltine Former Deputy Prime Minister Michael Heseltine was appointed as President in May 2019 and the current chairman (since December 2016) is Stephen Dorrell."