I believe both Globalcomm and Iridium are working on such a system using their satellite constellations. It can be done although it'd be kind of expensive for all of that satellite time (from $1 to several dollars a minute).

At any given time during the day, there are hundreds of airliners flying over the US. It'd take quite a bit of bandwidth to handle all of those telemetry streams. Some people have actually proposed monitoring those signals in realtime, but who would do that? You'd need a lot of people and that gets expensive in a hurry. Simply archiving the data and then playing it back after an emergency would be a lot easier.