Well the main goal of airlines is to make a profit no? . I am no fan of IATA and beancounters but here I have to admit they have a point.
Mandating changes without looking at the costs to the end user is a thing of the past. . We are now working with consensus and while nobody has a veto, everybody listen to the other side, and when what they say make sense , the group concur. This is how we now work in international technical panels , working groups and other bodies where regulations are being discussed.
The airlines have been fooled before in spending big $ on equipment that never been used as planned , think MLS supposed to replace completely ILS by the year 2000 to take only one of many examples..
To end this discussion :
a) in our particular Indonesian case here , the FDR and CVR have now been retrieved and FDR/CVR data streaming would only have speed up the results but not changed the outcome
b) Data streaming in real time will probably come naturally when 5G internet will be available via satellite at a fraction of the cost it is today, and one or 2 large countries would agree to build , run and secure a massive data center to store all this, and then agree not to used the data collected inside themselves, and that data will only be accessible to recognized Foreign National Accident Investigation Boards..
This is probably not going to happen in my lifetime.