You are not forced into anything, if you don't want to be put into "bubbles" use other services.
And ... this may be news to you, but every once in a while a large bubbling company may actually buy some upstart service where their own attempts at NIH entry into a niche fail.
You know, like Google buying YouTube in the first place.
Pretty sure that's incorrect. If I want to rate an app I purchased on Google Play with my Google account, with my Google smartphone, I need to post that review to Google+ even if I don't use or have a Google+ profile. That is lame, because I am forced to create a profile and use Google+ (in addition to having a basic Google account where my credit card and email are) just to submit a feedback score to the developer of the app.
Google forces its way between the task I'm undertaking - leaving a rating, and their Buzz 2.0 product which has nothing to do with me leaving a rating on an app I have paid money for.
Google can force whatever it likes on users as defaults, and I won't care one bit if they just allow options for users to change those default settings. Eg "don't use Google+", "don't hide editable subject field in the compose new message gmail window".