I was reading an article on the building materials shortage this morning. Among the various factors was that the cost of moving a 40ft shipping container from Asia to the west has risen from $1000 to $8000 in the last year 'becoz covid'. The article also went on about unprecedented demand for materials as people renovate their homes etc, the same can probably be said for the surge in bike sales last year (though I was rather hoping the 2nd hand market would be flooded by now with nearly new bike that people realise they didn't want afterall...)
Brexit is an issue, but not THE issue. A remainy mate of mine works for Maersk and says as much. When I was speaking to Ribble earlier this year about my delayed bike, the guy said that UK suppliers were shifting buying directly from Shimano Japan because they thought it might be quicker... But that is still beholden to the increased shipping costs.