So at face value this seems unfortunate but reasonable.
HBO likely overpaid for Sesame Street, possibly as a result of a private bidding war or just to ensure an even bigger bidding war didn't happen. A new CEO came in a few years ago, likely noticed some extra spending, but with HBO money it was easy to grow. With HBO gone and no one jumping to pick up the tab, a lot downsizing is reasonable.
Unfortunately... the timing also aligns with plans to unionize.
I expect more to this story in the coming months.