If the drive has|had the Hitachi brand on it you absolutely can say that's what brand of drive it is|was.

As I understand: WD bought HGST (Hitachi Global Storage Technologies), then sold on the manufacturing of 3.5" drives to Toshiba to comply with EU and FTC requirements (http://www.anandtech.com/show/5635/western-digital-to-sell-h...). WD retained the 2.5" side of the HGST manufacture.

I doubt anyone wants to buy a WD HGST branded drive on the strength of the past manufacture in what are now Toshiba owned factories. WD would want the past drives, sold as Hitachi, to be called HGST as it boosts that brand - but to some extent that would be misinformation.

So back to this:

>Some of the HGST drives listed were manufactured under their previous brand, Hitachi. //

Those Hitachi brand drives were it seems made in facilities that Toshiba own now. HGST is now a WD brand (though they were not quite one company as of Dec 2014) - unless the "Hitachi" drives were made in WD facilities the calling them HGST gives quite the wrong impression.

It's quite convoluted and I don't really follow HDD manufacture news that much; please correct me if I'm wrong.

This is my understanding as well, but as you note its very convoluted.

Which is why I'm sure the HGST label on the graphs is an honest mistake. The hard drive world was severely shaken up as Hitachi got bought out by WD, and then FTC / EU split that company up on monopoly grounds.

There's no need to use a conspiracy theory. Nonetheless, it seems like the super-reliable "Hitachi 7k3000" of old is in fact a Toshiba drive today.

That is exactly how i understand it as well. HGST, or all HDD from Hitachi are now basically under Toshiba. Those 2.5" HDD capacity that sold to WD are all under WD brand.