as a german i do not believe that brexit is actually a root of their problems. it is more that despite advantages thanks to brexit they still fucked it up because their government is a bunch of greedy grifters. eu membership at best takes away some of their power and averages the incompetence and ignorance over several countries (as every member exerts indirectly power over all the other members to some extent). also leaving eu is a long-term project. it's ridiculous to argue that it's a bad thing to do just because the immediate effects are negative. that's always the case if something fundamentally is changed. the eu is a huge bureaucratic self-service shop for the politicians and their minions.