According to a recent news article, the Alaska Department of Fish and Game (one of the largest wildlife agencies in the United States), indicated that it is only able to "place two or three black bears in need" in any given year. This year, to their credit, they have placed 8 cubs in the custody of captive facilities.
Unfortunately, this number pales in comparison to the number of orphaned cubs in need of placement. When I served as the Curator of Animals at the Alaska Wildlife Conservation Center near Anchorage, we easily received several calls a season for black bear and grizzly bear cubs in need of homes. Another facility also received polar bear cubs in need of placement, which drew national attention.
Two reasons black bears are difficult to place is because, like all bear species, they are long lived and because they are not deemed conservation sensitive. So space is an issue, aside from other husbandry needs. Even the individuals representing the most imperiled subspecies from the Southeastern states are making a comeback. Hence, sanctuaries and other facilities are limited in their ability to accommodate new orphaned black bears from any where. These are tough choices to make and unfortunately, as mentioned, many are euthanized.