They keep all the managers to make sure the remaining employees end up covering the work of the ones laid off:) Im sure they laid off a few managers here and there though

People who advocate for firing managers forget (or are too junior to have ever learned) that managers...were once the regular line employees, bu they did well enough at their jobs to get promoted into the positions of managing other employees so that the other employees could also do well in their jobs.

Managers are usually the most competent employees at actually getting shit done, because they have to do their own shit on top of managing what the employees are doing.

I have not worked anywhere where the above was actually true, except in the beginning when scaling an organization. In mature organizations managers are hired for having managerial experience, not getting shit done on the line.