If there is any form of cell coverage (or they passed any enroute), the mobile phone company should be able to triangulate the last reported position to at least narrow the area down.
$200 devices miraculously become $10000 devices once they have to be certified, something a cost-sensitive market tends to avoid.
Someone should be able to produce a simple standard device that can transmit this data and some inflight telemetry to help with accident analysis and missing aircraft.
If clever people can make a high-speed train run in a vacuum then this can't be a tough ask.
It does boggle the mind how backwards aviation can be.
Then again if you're puttering around with 60-year old engine technology you'd probably still consider a wind up clock revolutionary.
