@Wolf480pl @kaniini @Shamar @cwebber @starbreaker it is entirely possible. However, if they release the advert as CC By-SA (as that's what we're talking about here) that means now *I* can remix it, and so can everyone on the Internets. If it's an "evil corpo", that is not going to end well for them.
Hence, they will not release it under CC By-SA. And hence they will not use by CC By-SA artwork either.
There are other reasons too, obviously (like: rigidness of evil corpo's legal departments).