Genuinely curious, what alternatives were there in the 2000s? Did dependency on Russian gas doom German manufacturing or did it provide it 20 additional years of artificial life support?
Nuclear. The Schroeder government initiated the German nuclear phase-out (which was later reverted and re-reverted by Merkel). But rumor has it that the nuclear phase-out wasn't only motivated by the greens being anti-nuke, but also by Schroeder being interested in pushing gas instead.
Btw., after his chancellorship, Schroeder got a post at the Russian state gas supplier Gazprom.
His direct involvement with the Russian oil and gas sector (and, most likely, influence on their behalf) is a lot more recent than just 'the 2000s' [0][1].
Diversifying just a little bit would go a long way.
When Russia invaded Ukraine suddenly several LNG terminals gained regulatory approval, even though previously those projects were in bureaucratic purgatory for years.
In the context of the times it was the aim of Europe to integrate Russia into the EU zone.
Who gave Russia all that money to convert to capitalism after the fall of the wall? The US. Who wanted Russia to become a capitalistic nation? The west.
That it failed is in whose interest? And who is scared of Chinese influence? And who outsourced all their manufacturing to China?
You can never know. People in Germany have wildly divergent takes on what would be good for the country right now and some things that are acceptable to say in mainstream circles seem batshit insane to me.
At the time it was a perfectly rational decision that followed the liberal foreign policy dogma of the time, which advocated that we tie up unstable countries with economic trade, so they become less incentivized to create havoc. Let's please not rewrite history.