Okay, technically SSDs did exist in 2004 (since the 1980s, actually), but with a maximum size of about 20GB at the time so it doesn’t count.
Anyway.
Launching on 27 October, the game’s next expansion includes the unprecedented (until now) “minimum” PC hardware requirement, previously listed as a “recommended” spec. In theory, Shadowlands should work on a standard HDD, because a storage device is a storage device, but I’d expect the loading times are going to suck for players who haven’t recently upgraded their boxes. That’s because an SSD can read and write data at up to 520MB per second, but a standard HDD is limited to 125MB per second. It’s a big difference.
By listing an SSD as a minimum spec, I guess Blizzard is conveniently precluding complaints that “omg, the loading times suck”. I mean, those complaints are inevitable despite the minimum spec published two months before the expansion is out, but tech support can configure a “told you so, lol” auto-reply so there’s no legal basis for a Change.org petition. Which is probably also inevitable because this is the internet.
Anyway.
What’s perhaps more intriguing is that it’s 2020 and people are still playing World of Warcraft. This is a game that’s kept people clicking for over 15 years now, and first launched with an 800MHz CPU, 512MB RAM, 32MB GPU minimum spec. On 56K dialup, even. And the 2008 launch of Wrath of the Lich King introduced a “multi-button mouse with scroll wheel” recommended spec – who remembers when a mouse didn’t have those? This archive of World of Warcraft’s system requirements is like a museum exhibit of PC hardware innovations from the Intel Pentium III and AMD Athlon up, and I feel ooooold, yo.