Just as at present DFDR & CVR data is not routinely retrieved
DFDR data is routinely retrieved and analysed for FOQA purposes. It is normally done via a Quick Access Recorder which may or may not be streamed wirelessly when the aircraft is on the ground. If the QAR is not available or not fitted some airlines will simply pull the DFDR for replay instead.
The CVR is normally "protected" by legislation following an accident or serious incident. There is generally no legislation preventing its use in other circumstances however, most employer / employee agreements will constrain its use as a monitoring tool. (There may be other non-aviation specific legislation which constrains its use outside of the accident scenario.)
Be aware though, that in some states it is a legal requirement for the operator to routinely download the CVR to check that SOPs are being complied with.
Overall I would assume that everything you do or say can be monitored by someone should they wish to.
The cost of transmitting data via satellite is plummeting and the bandwidth is rocketing (pun intended) new constellations by Inmarsat (Gx) and Iridium (NEXT) are likely to see 50 meg / sec to from aircraft. Over Europe Inmarsat's alpha will see 70+ meg/sec.
By contrast live FDR needs about 1 meg an hour ish. (dependent on type, number and rate of parameters). Live voice is only 128kb/sec ish.
The cost you are offsetting by live streaming is not just the "lost aircraft where do we look cost" (a low frequency / high consequence event) but the routine cost of moving the data off the aircraft anyhow for FOQA by either ground based data link or engineers going and pulling / replacing cards.
Hmm that post ended up much longer than I meant!