I worked for another company acquired by Siemens and it went quite well. Profitable, full of world class people, chill atmosphere, and you get to work on some pretty amazing challenges.
It was a bureaucratic beast, for sure, but definitely the best place I've ever worked. That being said, this was a business unit that was very complimentary to a lot of their other BUs. So the acquisition was for growth, not to destroy competition.
In 1993 Siemens acquired ELWRO, Polish computer manufacturer (RIAD - IBM 360/370 mainframe clones for Russian/Indian market) and ZWUT, Polish telecommunication equipment manufacturer. They paid $38mln. First thing they did was to fire everyone from ELWRO. They also send manufacturing lines and unused parts stock back to Germany, and on top of it demolished manufacturing plants and sold off bare land. Good old German efficiency, scorched earth policy. 7 years later Siemens finished this "investment" by selling remaining telecomm part of the company to US investor Telect who planned to manufacture fiberoptic switches in Poland. Rumor has it Telect came to some sort of a deal with Nortel and closed manufacturing in Eastern Europe as a result.
And that was that, from Mainframe manufacturer to nothing in 7 years from Siemens acquisition.
Siemens buying a USSR-era IBM mainframe hardware clone manufacturing company ~28 years ago for a relatively small amount of money and then failing to do something useful with it seems very different from this story.