Bad governments that actively hinder progress on many fronts (just look for example at Wissing as a transport minister being completely anti train service, destroying infrastructure for the people, while dancing to the tune of car manufacturers), lining their own pockets, corruption, unfettered lobbyism and bad policies for education system added their weight to this.
A country can only take so much incapability and corruption, before things go downhill.
As a German I warn, we better watch Germany very closely, if the likes of AfD get to power. Way too many people are either desperate enough or uninformed enough or disappointed enough to vote for the far right bordering illegal.
This has all been in the making for a long time, due to previous and current governments. A party like FDP is very far removed from its originally held values, and would love to jump in bed with the far right AfD, if that brought them into the government again after the Ampel coalition. They are traitors of democracy basically, just like CDU.