I'm not asking rhetorically btw. You seem to be a couple steps ahead of me.
I don't know about that, but......IMO:
I would call Stroustrup misguided for a lot of reasons.
More seriously though, the design philosophy of C++ has always been, "if there is a language feature people want, make it available." I don't claim to read Stroustrup's mind, but adding garbage collection fits that design philosophy.
The other design philosophy of C++ is to try to make it fast. So most likely garbage collection in C++ will be an optional feature, that can be turned on or off. There is already a garbage collector like that available with GCC. Or possibly they will learn from Apple's experience, and make something like ARC, which is not exactly garbage collection, but still takes care of 99.99% of your memory issues. This article goes in depth on some of these issues, although it's looking at it from a mobile standpoint, not a server standpoint. I believe that story was covered on Slashdot, too.
Incidentally, I can't find any reference to where Stroustrup says garbage collection is inevitable. This seems to be his official position.