First, not all states have passed legislation that is needed to permit land banks. Second, this is difficult work, and existing land banks have limited capacity to handle high numbers of properties at a time. More funding and technical assistance would be needed to scale these efforts up to an adequate level.
Of course, new funds are hard to come by in the current fiscal environment, but this appears to be an instance where relatively modest investments have the potential to yield significant benefits, such as reduced crime stemming from vacant properties, lower municipal costs to limit property deterioration or provide services to neighborhoods that are largely vacant, higher property tax revenue derived from property values not being unduly depressed, and other benefits that may be realized.