In my experience, they come in waves. They come either as data centres seek to replace or renew existing drives, but as a result, there aren’t as many lower capacity drives available. Lately, I’ve only seen 10+TB drives under a recertified banner, though you can find lower capacity drives that are “refurbished” instead. They will have the power-on hours to match though, as these are the refuse from those sorts of drive replacements.

You may find better luck with local used marketplaces if you only need cheap storage. Otherwise, they do seem less common if you don’t need large capacity drives.