As a back sleeper, get a pillow or cushion under your knees/legs. Otherwise the arch of your back is in constant stress when you sleep and can lead to back problems. You can guess how I know.
No, bad example. Nokia failed because they were using windows mobile instead of Android.
In 2011 Nokia started using windows phone os which, at the time, no one knew if it was going to catch on. In 2014 Microsoft bought the phone division and kept the OS although at that point it was clear that it was not going to work out. Operation stopped in 2017.