There are physical limitations. An electron trap will have a minimum size. New ways for leaps and bounds need to be discovered. I think it's not reasonable to assume that both magnetic and electric storage have the same maximum density of infinity.
How many years it will take to write 120TB on it?
A 120TB flash array can be written in minutes with enough upstream bandwidth, and takes just one rack.
Tape on other hand was always speed limited, is just fine in its nice with that limitation.