After 15 years, I just got rid of my last Drobo product. I saved up for a used original Drobo in 2011, and just today retired my Drobo 5N and gave it to a friend.
I still think about Drobo regularly - it was innovative technology deployed really well, and with style. Disks were expensive back then ($150/TB adjusted for inflation!) and people wanted to buy an extra terabyte at a time instead of having to do a big migration every time they needed more storage.
It was perfect for consumers who were price-sensitive enough that buying bigger and bigger drives was not an option, but buying an elastic NAS was still within their price range.
If you had less money, you couldn't afford one. But if you had *more* money, you had no need for a Drobo. Why spend $500 on an elastic NAS that could scale to 40TB when a single 20TB drive only cost $600 in 2020? Not to mention the rise of cloud storage and its plummet in price, the rise of high-efficiency media compression, etc.
Every time I think about building a new product, I remember Drobo. Technically solid, elegantly built, impressively designed, but useful for only a tiny subset of users for about a decade.