You can't just slap any old device into an aircraft and call it done. There's huge amounts of money + time that must be invested to get it certified, and it has

You can't just slap any old device into an aircraft and call it done. There's huge amounts of money + time that must be invested to get it certified, and it has to be done for each aircraft type. I haven't looked it up, but I'd wager an Iridium transmitter for transport aircraft would be in the 10s of thousands of dollars, minimum.