I doubt it. Intel can't even publicly confirm that they're inside of the iPhone, just listen to the execs when anybody even mentions the iPhone.
I think the margins on these modems are low because Intel has to pay TSMC to build them as well as third party packaging & test, but I don't think they're zero or negative. And I suspect they will only get better with 7560 (internally built modem) and beyond.
IMO, this is a pretty decent business for Intel. I wouldn't write it off as just PR/publicity.