IIRC, H&R went bankrupt and then reorganized by the former management team to become New England Firearms. When production started again, the tooling for the 999 and the 199 (my favorite of all their products) was out dated and worn out. They would have had to sell for the price of Smith & Wesson to get new equipment. The Partner was changed to quality cast steel and simplified to the Handi-Rifle, that was a great seller but not a high profit product. Single shot shotguns were a hard sell anytime.
Marlin bought them and ran for a couple of years, then to Remington and then Remington was "milk cow"ed out to the end. All very sad.