Blizzard died sometime ago, around these events:
1. When WoW hit it big, it made Activision want to turn almost everything into a MMO / always-online game.
2. See above - that's why D3 went always-online on PC...among some other reasons (DRM to try to stop piracy, try to stop players from cheating, force players to play together, etc).
3. Core Blizzard guys left & split-up, with some going to form Runic (Torchlight games), Flagship (HGL - that studio died), etc.
Blizzard's dead. D3 was the nail in the coffin in many ways and the sign of the times - while RoS improved and fixed a lot, that game got dumbed-down ARPG-wise (stat-wise & character-build wise) BIG TIME. Their corporate take-over by Blizzard happened already, by then.
BioWare's on this same path, namely after ME: Andromeda and Anthem.
Also,
ZA/UM is next; and so is probably Rockstar (since Dan Houser, Benzies, and Lazlow left).