Have I missed something here? You get a cut down new version free, but are able to continue to use your bought full version plus all your 3rd party bought plugins etc. in tandem. Is that right?
The BandLab users now get to use a mini Sonar, will love it, and then BandLab will develop it. If you don't like what they do, you continue to use what you have bought.
I bought a lovely new car two years ago, but the manufacturer sold out and the new guys have since brought out a new improved model - I am entitled to a new car? I think not.