I agree that the strain on the welfare state will be the most influential factor that kills Germany. As things stand and continue to develop, I guess that Germany will enter future history books as the single-most retarded country in the history of mankind - hand in hand with Sweden - which, without any rhyme or reason, will have terminated itself in this bizarre manner. There is no politician on the planet that could justify expending hundreds of billions of EUR year after year on a self-inflicted 'refugee crisis', while at the same time watching as the country's infrastructure and judicial system continue to crumble. The german populace can see that too, and they are clearly not liking it.
As things are developing, I can only estimate that soon the broader masses of Germans will increasingly realize that the judicial system is more or less defunct by now (depending on the federal state you're in, at the moment) and that the state's monopoly of legitimate use of force is practically off the table. And if the state claims that monopoly, but can't deliver protection via police etc anymore, people will increasingly arm, defend and fight for themselves. It's the only reasonable thing to do. Self-arming is already happening (http://www.epochtimes.de/politik/deutschland/deutsche-bewaffnen-sich-wegen-fluechtlingskrise-fast-eine-halbe-million-buerger-verfuegt-ueber-kleinen-waffenschein-a2019626.html). As it is very difficult to get real legal gun permissions as a civilian, people buy what they can get legally. And there's quite a lot of illegal arms dealing happening in dark alleyways, where the real goods are exchanged.
If Germany decays, so will the EU. Europe will - once again - have one hell of a rude awakening. So much seems certain. Will they ever learn? I have doubts.
Going to England would be an option, yes. There's a reason why the EU, I mean Merkel, must prevent Brexit really happening at all costs. If the UK leaves, the so-called blocking minority of 35% consisting of the populations of England, Netherlands, Austria, Germany and Finland, is off the table (http://www.hanswernersinn.de/de/Interview_Euro_11072016). If that happens, the southern european countries will have guaranteed majorities in any votes to come in the EU and Germany will become the eternal idiot paymaster for the southern countries. Also, UK leaving is economically equivalent to about 19 other european countries - the small ones - leaving together. That should tell everything there is to tell. So, Merkel is practically losing her shit over the prospects of the UK leaving that slave union called EU.