Rooftop solar is prohibitively expensive in Germany. My installation would only cover its costs if electricity becomes so expensive that it would lead to complete economic collapse.
No. In Germany, rooftop solar is usually economically attractive, not prohibitively expensive. Especially on a decent roof and if you use a fair share of the power yourself. Verbraucherzentrale(1) says PV systems for private homes are “usually worthwhile” economically, and that self-consumption is the key driver of profitability.
(1) https://www.verbraucherzentrale.de/wissen/energie/erneuerbar...