Not speaking to the airline pros out there
Be mindful as well of why commercial aircraft have FDR/CVRs in the first place. They are there to help accident investigators find out post hoc why the aircraft arrived at the incident/crash site. What they aren’t for is real time data analysis for maintenance or looking for cost savings. Some aircraft have systems that do these jobs and a separate data stream for that purpose. It is difficult, if not well neigh impossible to factor out willful abuse/neglect by human beings in the chain if they are determined to do things like fly into a mountain like Germanwings 9525 in 2015, or find a method of circumventing a transponder. What you can do is satisfy what factors led to the crash. Every improvement in airline safety today has been paid for in blood and tears.
Personally, I think it’s only a matter of time before the bandwidth is sufficiently inexpensive that something like real time telemetry of most commercial flights is a reality, much like instrumented military ranges are for fighters. I also think it will be a decade or more away and will likely be an extension of ACARS. Maybe Tesla, Google and Boeing will team up and make massively inter networked airliners. 