Next next next gen object stores
Ridiculously late to the party.... oops!
Even more entries in the mix now in 2021 with ONTAP and OneFS having S3 adaptors added to them, and in the world of software-defined I see Nutanix too has a s/w defined object solution on their platform (lots more features than I expected) - plus Azure's Blob is another public cloud object solution to look at (Azure mentioned in article but not Blob specifically)
Also found this which is interesting https://www.gartner.com/reviews/market/distributed-file-systems-and-object-storage