If this business goes on much longer, airlines are going to start losing Business Class passengers in large numbers....
I'm not sure that is true, afterall, if you need to travel from London to Munich then you don't really have much of choice other than to fly. The restrictions apply whichever airline you choose. If you're thinking about driving to such locations then the extra time taken would indicate that a couple of hours without your laptop in an airport is not a problem. Additionally, business class travellers have plenty of IT facilities in the airside lounges. The only occasion I would look at train travel would be if I was travelling from London to Paris or Brussels, Eurostar (the passenger service rather than Eurotunnel which is the car 'drive on' service) is already a viable alternative to those destinations.
Airlines are going to have to come up with some better solutions than the extreme measures being inflicted on business travellers from the UK if they are to retain our custom - I am now looking at Eurotunnel instead.
These restrictions have nothing to do with the airlines