To be honest I'm not sure. It seems like _a ton_ of work to put out a high quality translation. I do not know how much time and money translators spend on each project but can imagine it being a lot. For example, some authors may expect a legit highly-paid translator to work with their own German proofreader etc to ensure quality of the output.

(Tangentially, I think Germany has some special laws that you as the translator would need to be familiar with. For example I think the translator needs to grant rights to the original author to republish the work. Not 100% sure on this, but worth checking!)