I actually came here to post the same thing. I presume somebody has already posted the link to the Ubisoft official statement about how they're slowly phasing all of the 2011 content out of the store ( https://discussions.ubisoft.com/topic/111873/rocksmith-2011-dlc-delisting?lang=en-US ).
1) For Ubisoft to take them off the store means their license to sell them expired on that date. For them to not transfer it over to the 2015 store means they don't want to pay for a new license. They are abandoning it from a legal sense.
2) Shouldn't that make all of these titles fair game for CDLC? There's no place to legally buy them effective that date, right?
I think I'll put in a request for Freebird.
Actually, never mind. According to staff member coldrampage those tracks are gone forever. Apparently CF (despite not saying so in the FAQ or the Guidelines) actually refuses to touch any song that's ever touched Ubi's hands, even if the license is dead.
No explanation was provided and I got the distinct feeling this was either a very old fight I'd wandered into as a newbie, or I'd asked a patently foolish question. Maybe Freebird is a lame stupid thing to ask for around here? I dunno, but I literally got laughed at. Maybe admins should get their finger out and put it in the FAQ?............. but again, I don't get the sensation there's a lot of fresh faces asking questions around here since 2015.
Final answer: RS11 tracks are gone forever, don't ask anymore, literally nobody cares.