By "ruin" I mean the less tangible parts of the smaller company, such as the culture, the enthusiasm and spirit, the flexibility, the overall happiness.
Having now been in two medium-sized companies that have been acquired by large, public firms, I find that everything we enjoyed is gone. Perks slowly disappear; meetings, trainings, and general wastes of time increase; productivity slows; engineers become demoralized; processes grind through bureaucracy. As I understand it, this is typical.
What are some examples where acquisitions like this have happened and the smaller company wasn't essentially destroyed?