I believe this solution could be done a lot cheaper.
There are many other factors for hikers besides cost.
Foremost, any equipment designed for use in a life-and-death situation must be ultra-reliable, otherwise, it is pointless.
It would have to be durable enough to withstand being jammed into a pack with other objects, knocked against trees, leaned against and generally mistreated and still do its job when most needed.
It would have to have enough power to fly for as many miles as might be necessary. There are many parts of the Western hemisphere (e.g. Canada, Alaska, the Andes) where a phone signal might be very far away. Also, don't forget weather conditions. High winds, heavy rain or snow & ice must not defeat your rescue drone.
You'd need to equip it to be able to independently tell the rescuers where the imperiled hiker is located. You cannot assume the hiker would be able to convey this information. You'd need to design it to interface seamlessly with an existing network for search and rescue. Otherwise, who will it be talking to and how would they know what to do?
It would have to be small enough to justify the space it takes up in one's pack. And, as noted already, it would also need to be lightweight. Bulky or heavy items tend to be left behind.
Solve all these problems more cheaply and reliably than what is already out there and you might have a winner.