Because at most places lead/lower management is another word for yes men that have proven their blind loyalty to the CTO, usually for 2 or 3 years. They don't wanna hire a manager who may question the status quo, especially when it comes to architecture and best practices.
> The market value for a profile like mine in a big German city seems to be around 100k € including some small bonus.
That sounds low to me and attainable in Europe if you have 5+ YoE at the right places. It sounds to me like you are being lowballed. I'm getting similar offers with way less experience.