The current case has zero problems with technical security - it's the ages-old problem of someone holding money of consumers and then running off with it.

There's a single solution (that bitcoiners tend to dislike) - regulate all such entities, requiring them to (a) verify their identities, and (b) post bonds/statutory capital in proportion to all held funds, to ensure that depositors are paid back if the company folds or turns out to be a fraud, i.e., the same rules as banks have to follow.