Once again, there is a difference between sovereign debt and personal / corporate debt. Subprime mortgages are subprime because the debtor has a risk of default, the US prints it's own currency, issues debt in its own currency, has some of the strongest institutions in the world, and controls the global reserve currency. The risk of default is essentially nil. When governments spend money on infrastructure and health / education the ROI is positive.

Germany is not in a position to print the reserve currency of the planet.

I'm not advocating for Germany to go all MMT here, but negative bonds are a clear indication that government has ample room for debt financing. Germany has notoriously poor internet service, investing in broadband infrastructure could help them transition into more of a service economy, which would be a smart hedge as the slowdown in Chinese consumption led to a slowdown in consumers buying German cars and a contraction last quarter. Also as mentioned, all the European players are big on tackling climate change -- why not fund solutions? Instead, Europeans leaders like Macron have gone with the politically infeasible route of higher petrol prices.

Germany has invested substantially into tackling climate change. Google "Energiewende".

Maybe also do some research on the internet infrastructure in Germany. It's a cartel. That's why service is so bad.

I'm not saying I'm against good infrastructure investments. But just telling us to "keep spending" because "debt is cheap" won't cut it.

Things may very well be different this time, but there aren't many examples of government backed internet investments working since the 80's.