Bluetooth 5 introduced "coded PHY", which allows ranges of over 1 km in ideal conditions. As I understand it, adding support for this wouldn't even require new hardware for most recent phones.

The real obstacles here are political, not technical, as evidenced by the complete absence of any built-in solution that could be so useful in both everyday life (messaging a family member on the same plane when sitting separately, national park trips etc.) and emergencies.

We literally got smartphone-to-satellite comms now, but we're lacking the most barebones peer-to-peer functionality.