Wage theft and fraud are crimes that state attorneys general do prosecute.
https://www.atg.wa.gov/news/news-releases/attorney-general-f...
https://www.atg.wa.gov/news/news-releases/attorney-general-f...
It likely was once promises were made to continue to pay severance for at least one year, and employees relied upon this promise (instead of immediately seeking to work elsewhere).
It's not technically wage theft, in spirit it's pretty similar to wage theft since the termination of employment contracts had severance payment as a clause.
Potato, potato.