It was Notch's dying wish and command, despite his full divestment from the game, that grizzly bears never be added in because his ex-wife once said she would feel more comfortable running into a grizzly in the Dark Forest biome than him

Grizzly bears are offensive to certain men, who are generally seen as more dangerous than grizzly bears by women who are lost in the woods. Minecraft didn't add them because they have capitulated to the Woke Mob.

Grizzly bear fur is highly profitable to Villagers. Long ago, the Villagers built Iron Golems that hunted the Grizzlys to near extinction. You are living in the long-term aftermath of this. The few that got rich from the bear fur trade have spent all of their riches and are just as poor as the other Villagers. Most of the Golems were destroyed by the Illagers. The Grizzlys are now all but extinct, they are survived by their Polar and Panda brothers.

P.S. The Player is the last of their kind. Everyone else was infected by the Zombie virus.