30Mb/s for realtime telemetry sounds a little over the top
It
is over the top.
But the principle is sound, that continuous transmission of all FDR data from commercial aircraft would far exceed available satellite capacity. And extending that capacity to the extent required would be extremely expensive. This was discussed at great length in the FH370 threads, and little has changed since then.
Simple position reporting on a continuous basis _is_ feasible, however it doesn't seem that this would provide much additional evidence in the present case since the aircraft was in primary radar coverage when lost.