Sigh. Another article written, it seems, by someone who thinks that all/most software development is on the web. "Storage systems" in the cloud ... it might make you feel good to pretend that this is really just a variant of storage systems on your local NVMe unit, and that therefore the APIs involved really ought to converge. But this is an illusion likely caused by insufficient native development experierence.
The author needs to ask themselves: in this cloud technology stack, is there POSIX involved somewhere lower down, where I can't access it? The answer is, of course, "yes". The sort of cloud storage systems described all run on top of POSIX APIs. They provide convenience (cost efficiency is more debatable) compared to the POSIX alternative, but that's because they exist at an entirely different conceptual layer (hence the presence of POSIX anyway, just buried).
There's about as much reason to expect a single API to access the filesystem attached to the PCI bus and an unstructured storage system as there is to have a single API to create a PDF of a document AND deliver it to the printer. Which is to say: the higher level abstraction will use the lower level anyway, but it exists for a reason, and isn't appropriate for everything.
The author needs to ask themselves: in this cloud technology stack, is there POSIX involved somewhere lower down, where I can't access it? The answer is, of course, "yes". The sort of cloud storage systems described all run on top of POSIX APIs. They provide convenience (cost efficiency is more debatable) compared to the POSIX alternative, but that's because they exist at an entirely different conceptual layer (hence the presence of POSIX anyway, just buried).
There's about as much reason to expect a single API to access the filesystem attached to the PCI bus and an unstructured storage system as there is to have a single API to create a PDF of a document AND deliver it to the printer. Which is to say: the higher level abstraction will use the lower level anyway, but it exists for a reason, and isn't appropriate for everything.