Who says that?I don't think you understand what Blizzard is doing. They nerfed the Old Gods to the ground, but the Old Gods have hivemind themes. Il'gynoth is described as being part of N'zoth, while also acting as a separate entity with its own name. Same goes for each and every Faceless One.
The current idea for Old Gods is probably that the Void Lords are the Old Gods, in the same way N'zoth is Il'gynoth. That's how they're resolving the power level questions, where they've been using Old Gods at two very different power levels. The solution is to split them up into the physical manifestation of Void, the Old Gods, and the incorporeal and deathless spirit of the Void, the Void Lords.