Automation can minimize labor costs but it cannot eliminate them because it is not economical to automate all jobs even when it is technologically possible to do so.
The only thing stopping that is that it's still too expensive to build machines to do certain jobs. But that won't last forever. Eventually, with the progress of technology, it will become very economical to replace workers with machines. Some jobs may require a robot that requires 20 years to pay itself off, that probably isn't worth it for a lot of businesses. Some jobs will pay off the machine in 2 or 3 years. At that point, as far as the company is concerned, it's economically irresponsible to not get the robot to do the job. As the cost of the machines come down, that machine that used to take 20 years to pay off, will only take 10, or 5, and eventually it will be cheap enough. The only jobs left will be thinking/creative jobs (unless there is some major advancement in AI), and jobs that people actually want to talk to a person for. As annoyed as people get with customer support personnel, they would be infinitely more annoyed at a machine who was reading off the same script.
expensive drives that wear out or can mangle the tape
This is my main problem with removable magnetic media. The simple act of reading the data actually degrades the storage medium. And if you have a bad drive, it can actively destroy any disk/tape you put in there. And it's actually hard to diagnose if the problem is with the disk or the drive, so you're likely to destroy a few disks/tapes before you figure it out. I've had floppy drives, zip drives and tape drives that have all ruined the storage media. At least with optical drives, it's very unlikely that the disc will be destroyed by attempting to read it.
A rolling disk gathers no MOS.