There s no issue, whoever want to manufacture the thing using this methodology will pay some bucks to the patent holders, and as said fees are negligible compared to the RD cost.
A single licencee along with AMD s own production wont be enough to amortize the RD costs, one way or another they knew from the start that broadly licencing the tech was mandatory..
As for the induced cost it should be 1-2$ for a 500$ card, that s about negligible in respect of the manufacturing induced savings.
Well, dont worry, you ll have Nvidia HBM equipped cards next year, just that AMD will also be first to HBM2 and will have a few months advantage as they can use experimental HBM2 dies with their next GPU without having to wait for the process being validated, that s essentialy what they did with Fury.