You seem to be putting a lot of emphasis on the "private feed" feature, almost making it sound as if you're scared all the good feeds will go silent overnight. I don't see that happening. We all started these feeds expressly for the public to have access to them, not to have a private club with a $180 a year membership fee. You do realize that the ability to set your feed private is an option, correct? Subscribing to the premium features does not automatically make a feed private.
Consider instead the benefits to RR premium members (paid or feed providers) if a feed providers signs up for these premium features, notably concerning the archives. Now instead of having to listen to 30 minutes of mostly silence to hear a call from the past, the archive will be automatically trimmed of silence and you can listen right through. That 30 minute archive file might now be down to 5 minutes of solid action. Also the fact that the archives will be available for 3 months on those feeds is a really nice thing to have, in stark contrast to the 15 day limit on free feeds.
Remember, all of this stuff is optional, and it doesn't take away anything from the current setup, it only adds. I don't believe there is any reason to panic in thinking that all the good feeds will suddenly go private.