There are a lot of people who have advocated eliminating filesystems.
However, they have always run into the stumbling block that it's just impractical to deal with all hunks of data in a flat namespace. Directories are EVIL, but nobody has make anything else work even one tenth as well
Also, just keeping everything in ram falls apart as soon as you want someone else to access it (or you loose the device, or the device gets destroyed, or ...)
Many of the people pushing back have been though this "eliminate filesystems" experiment before and have the scars to show for it. Listen and learn (then go try and build something to prove them wrong :-)