I'm a noob here, so please excuse me if this is a stupid question ...

But why are these kinds of claims not being brought to court and/or arbitration?  If someone has custody of your assets and their actions prevent you from accessing your assets, they have committed conversion - theft, as well as breach of fiduciary duty.

Blockchain.info/Blockchain.com is a real company with a real business registration. It can be sued. And given the value of the assets in dispute here, it should be taken to court/arbitration by you and anyone else losing more than one BTC or so.