Researchers have developed a Very Big Disc™ that can store up to 200 terabytes of data and may represent a return to optical media for long term storage
The discs are said to be highly stable, with an expected lifespan of 50 to 100 years. That's a huge leap over current data centre HDD based storage systems, which generally move data over to new devices every five to 10 years to avoid data-loss from ageing drives.
Many do, for long term archival at least, but tape still has only 30 years lifespan and has other limitations. As an example, the media wears relatively quickly when in use, so if there's a need to access the data even relatively often optical media would make sense. That's often not an issue in archival though.