I think one of their big mistakes was falling for silicon valley's BS, namely Android TV. I think many of the issues with B&O's Android TVs are directly traceable to Android itself (i.e. Sony can't even make it work).
I've seen this movie before: Management loves the "Android strategy" - license an "industry standard" "platform", and automatically get access to the "smart" apps everyone is clamoring for. Fewer engineers required? Even better! Some of the remaining engineers try to make it work, realize first hand what a pile of crap Android is, and push back. However, those "trouble makers" get pushed out for being "resistant to change". The rest put out their resumes. Some of the best and brightest leave. The downward spiral goes on...