Delta does sometimes use a spare Song aircraft as a substitute for mainline equipment if need be. Most customers don't mind, the upgraded Medallion passengers are given free additional upgrades on later flights, and the flight is flown with DL
flight attendants and one Song flight attendant who can assist in helping with the IFE if needed.
Delta has recently been using a Song airplane for flights from ATL
in order to allow those passengers to experience what Song has to offer.
Your post isn't holding water. Song aircraft are already owned by Delta, but they operate as a seperate entity. As far as them being folded up, where did you hear that? There are some folks on here who would love to see that happen sooner rather than later, but Jerry Grinstein has said himself that Song is making money and doing better than even he expected it to do. So whoever gave you your understanding wasn't telling you the truth.
I don't have a microwave, but I do have a clock that occasionally cooks shit.