Coincidentally, there's a cheaper way too. :)
The ratings of existing power lines can be recalculated on an hourly basis according to outdoor temperature and wind.
That however, requires software and agility, which big companies seldom have... and it doesn't help during a heat wave with no wind, of course.
I played the idea a few years back, at some anarchist-leaning not-just-music festival. We tried setting up a link over a 70 m hill, both stations using 433 MHz (500 mW transmit power, quarter wave antennas) narrowband (no frequency hopping) LoRa boards from Chengdu EByte. Stick antennas, not directional. Both stations were right below the hillside, so the hill formed a perfect obstacle between them.
Communicating over the hill in a single hop proved impossible. With a repeater at the hilltop, it was possible to make contact with the repeater from street level (no line of sight, trees obstructing), but the repeater (Meshtastic didn't exist back then, it was entirely homebrew) had software bugs, so - no link to the other hillside. :)
With better software and better planning, the experiment would have succeeded. :) And if we'd have tried building a link over a valley, it would have been considerably easier.
With ordinary WiFi and directional antennas (panel or ladder antennas), I've been able to establish links over 1 km. If one used a LoRa card, and had a directional antenna for the frequency involved, in clear line of sight, I believe 10 km would be attainable without being a radio specialist.