The obvious way to keeping the defence base warm, an important part of any National Security Strategy, is to have a European defence procurement program. Each nation’s defence industry provides a particular piece of kit for all of EU, with total program benefits equalling out for each country.
I know that sounds hopelessly naive but recent events do seem to alerted politicians to the value of having a functioning defence production infrastructure.
In any case, as a Canadian I probably should not be lecturing anyone on defence production policy as Canada is a case study on how not to do defence procurement with the Cyclone Helicopter and the National Ship Building strategy as sad examples of how to maximize cost while minimizing capability.