Even in 2012, if a laptop didn't have an SSD, it wasn't high-end. Similarly for a database box.
Remember that most desktop users aren't running Linux with a minimal desktop environment. They're running some iteration of Windows. For a lot of these users, adding more cores won't help them go faster, since the giant precompiled binaries they run can't (yet) use all the cores. Adding an SSD always helps, though. That's why users are buying SSDs in droves.
Hard drive prices also never quite recovered from the flooding in Thailand. This shouldn't really be surprising: why should manufacturers plow more investment into a dying technology?
Hard drives will remain relevant for a while for people who want to store huge amounts of data. But they'll be a specialty item, like liquid-cooled cases or CRT monitors (remember those?) In 5 to 10 years, talking about hard drives will immediately identify you as an old person, just like reminiscing about those blurry CRT monitors we stared at in our youth.