Well, I don't normally consider quadrupling of maximum storage capacity in a few years' time "stagnant", but it's true that speeds haven't gone up much in the last few years (at least with IDE; SCSI drives have gone up to 15KRPM and improved notably in performance). Certainly hard drives are a performance bottleneck for almost any modern system.
There does not appear to be anything immediately coming up that will displace magnetic hard drives. MRAM looked kind of promising, but has remained extremely expensive and hard to manufacture. There's work being done on holographic storage, but nobody has gotten it beyond very early laboratory prototypes.
Discussion Zen 5 Speculation (EPYC Turin and Strix Point/Granite Ridge - Ryzen 9000)
Discussion Intel current and future Lakes & Rapids thread
