I think people underestimate the price of owning a car vs. renting one. I can rent a VW Golf in Berlin for <350 EUR per week, 1000km included. The ADAC (car owners association) puts the monthly price tag for owning such a car at > 500 EUR per month. (assuming you buy it new, own it for 5 years and drive 15000km/year) https://www.adac.de/_mmm/pdf/autokostenuebersicht_47085.pdf
That means I can rent that car for ~5 month and still come out ahead.