Interpreted the other way, I don’t think that makes sense because on the whole storage has always gotten cheaper with time. Hard drives may cost the same, but they’re larger capacity so really this would only work as an argument if hard drive storage space stayed the same and prices remained the same for consumers but went down for manufacturers.
Also there’s a lot of competition in the space similar to other chips so I don’t see how a company making NAND or platters can afford to sit on their hands like that. The whole point of drive innovation right now is to drive the price per GB down for B2B sales. And that usually translates well to consumer sales too.
It looks like it depends on the drive size but also I think the pandemic has leveled this out in recent years. Some additional data I found by BackBlaze shows a bit more of the story though they have changed their drive sizes which leads to a more interesting graph.