@jzb Sure, but this is completely solveable at a technical level and would be solved if anyone either cared enough to do it or were forced to by (say) federal law. The fact that two organizations are involved doesn't make it that much harder to solve. The whole reason they operate by periodically exporting batch lists of contacts is because there is no pressure for them to do something that's more compatible with real-time updates to the list.

It's not because they can't; it's because they don't.