It doesn’t matter and we shouldn’t care. If the crew is abandoned the port state should be able to sieze the ship. That would force whoever owns the thing to crawl out from under a rock somewhere or lose his investment.
The port state has the power to put a guard on the ship and prevent working cargo. Too bad if it can’t be unloaded. When shippers get burned as badly as the crew maybe they will demand more assurances that they are dealing with legitimate operators.
If the crewing agency loses their commission then so be it, let them share the risk of dealing with scumbag operators. See the above, when the beneficial owners are threatened with the loss of their investment they will crawl out from under the rocks.
As far as this idea of anonymity of owners or operators go, this is a national security issue and should be treated as such. There are laws covering money laundering, the IMO numbering system was developed to help prevent bad actors from using ships for terrorism, smuggling, or economic crimes. If the beneficial owner cannot be found then it should be an automatic reason for seizure of the vessel by the port state. What surprises me is in this day and age those ships with such shady ownership are even permitted to enter a US port.
If the US can enforce laws that allow a police department to confiscate the house of an old widow because her son got caught smoking weed then surely we can take equal measures to prevent the obscene practice of abandoning crews.