Bad headline: WD acquired Hitachi Global Storage Technologies.
The Hitachi company itself is a monster that makes WD look like a mom & pop operation. What you see as a consumer is dwarfed by its industrial products and much, much more.
There's something about these large Japanese conglomerates that just don't seem to have any parallel in the US. GE might be the closest thing, but even though it's a larger company it doesn't seem to have the finger-in-every-pie feel that these Asian conglomerates do (e.g., Hyundai, Fuji, Mitsubishi, ...)
The US definitely has parallels. You can take almost any brand, and trace it back to a handful of large corporations. The Japanese are just more open about it, whereas US companies have subsidiaries that falsely suggest competition.
The Hitachi company itself is a monster that makes WD look like a mom & pop operation. What you see as a consumer is dwarfed by its industrial products and much, much more.