This is seriously madness. As an expat entrepreneur living in Berlin, I can honestly say that I'll leave Germany and take all my tax money with me if this law passes. Being an entrepreneur and a foreigner here already has many drawbacks including the obligation to pay for the same health insurance Germans enjoy freely while paying the same or higher income taxes. I have little intention of retiring here, but even if I did, the chances of social security even being around by then is slim and wouldn't be enough to live on anyway.
This is especially bad news for the Berlin startup scene which has been experiencing such incredible growth in imagination and momentum lately.