They actually (mostly) fixed this recently (in no small part due to being beaten down pretty hard by iFixIt a few years ago filing a crazy number of new exemption requests ;P). Now existing exemptions have a streamlined renewal process where the opposition needs to demonstrate that there was an important shift in the underlying evidence during that time.

https://clinic.cyber.harvard.edu/2017/10/25/update-on-the-20...

https://www.copyright.gov/1201/1201_streamlined_renewal_tran...