I should think in reality there's a lot of blame to go round, both Gibson and Cakewalk. At the end of the day Cakewalk were responsible for the direction the program was headed, and that direction was not enough to attract new users in the kind of numbers that would have saved the company. I've said it a lot before and I still think it's true - Cakewalk did not do enough to attract fresh new amateur bedroom producers.
These kids aren't miking up drums and guitars and soundproofing rooms and recording bands, they're using synths and samplers and a plethora of modern electronic production techniques to make contemporary styles of music, and they're doing it in small rooms on headphones. There was literally nothing steering this market demographic to Sonar instead of FL and Ableton. Pro Tools has the pro studio market cornered, and it was frequently apparent to me that Sonar's core base continued to be older guys who write and produce more traditional forms of music.
Ask the question "how long have you been using Sonar" either on this forum or the Facebook groups, and 90% of the answers will be along the lines of "Since the DOS days - here's a photo of my original floppies!" or "been using it since 1998." You'll be lucky to see a single person who says they just started using it. It had an image as a long in the tooth DAW popular with aging guitarists, even though it is better than things like Ableton and FL in so many ways. Many here never saw a problem with that and said they were happy to use a program which doesn't appeal to kids. Well, those kids have money - their parent's money - and Cakewalk needed it. Desperately.