Yeah, this is looking more like a total CF.
Initially, they were going by the accident reports - then from there, they've isolated to a possible inflator design / chemical load. Note, that this doesn't mean that every other airbag (non-Takata) out there is 100% safe. From a statistical standpoint - these defective airbags don't vary much from other airbag manufacturers - as they average about 17-20 deaths annually related to airbag injuries.
Another issue could be related to poor records management on Takata's side. They don't know where all the defective airbags went, so that puts the weight on the end manufacturer to check/test their stock. Some companies just blanket recalled any Takata airbag, just to err on the side of caution.
Important to note that not ALL of Takata airbags have been proven problematic - right now, they think they found the possible culprit design. Hard to nail down a possible defect when there are more than 10 different airbag inflator designs from the same company, with different chemical gas generators.
More concerning - recent reports seem to point to even the revised Takata airbags with a vented inflator and non-corrosive/less powerful charge are having new issues! Details of which are still pending.