This often started with off the shelf wireless APs (like the venerable D-Link DWL-900AP+ with often home made antennas connected. If the network had more knowledgeable Unix people, they might have used an old PC running Linux or BSD with hostapd and an PCI wireless card. The most advanced ones even had home-built optical links (Seriously, 10 Mbit/s full duplex on 2001 by light was super cool! https://en.wikipedia.org/wiki/RONJA) though our network was not that hardcore. :P We did lay some cable via agricultural pipe and build a makeshift com tower next to a Vineyard. :)
Over time the networks got high larger via bridging and wired or even fiber segments and a lot of the hardware was often replaced by high performance Microtik and Ubiquity devices.
Also the networks often merged into bigger ones, covering whole cities and their surrounding villages, with APs on top of grain silos and water towers.
Some of the networks are still independent and quite big, some were bought by big "traditional" telecom companies and some still operate as user coops to this day.
With high gain antennas you simultaneously increase mutual reception and decrease reception of other signals, giving a triple boost to your signal-to-noise ratio if you can use it on both sides (sender: +1 txpower; receiver: +1 signal reception, +1 interference rejection), so that is what you should aim for.
Transmit power does comparatively little (sender only: +1 txpower, -? amplifier noise), while blanketing the area with useless power (both in-band and out-of-band²) that can get you detected and affect other devices. Especially if you driver you transmitter near the limit (or use a shitty amplifier, broadband antenna) further increasing out-of-band transmissions, which is the part that is likely to get you a visit from regulators.
¹ gain ~ directionality; symmetric in both reception and transmission
² out-of-band - frequencies other than intended ones