Lol... no. There are so many flawed assumptions here I'm not sure where to start. Basically everything you said was wrong.
First, the "neighbor house" would typically be hundreds of yards away at the absolute closest.
Second, the availability of water for fire fighting purposes in rural areas is commonly dubious normally. It's exceedingly rare that a residence will have any form of pressurized water like "personal hydrant" type of system. At best, they might have a 2,500 gallon polyethylene tank, or a pond they could dip into, IF the volunteer fire department has a pump and hose setup, which is itself kind of rare or slow to arrive.
Third, a lot of the efforts on scene are unlikely to involve water at all. It's more like wild-land fire style where you might try to cut fire lines and stuff to try and prevent igniting surrounding areas, evacuate and render aid to affected people, etc.
If they really are building on multi-acre lots then you're probably right. But if it's more like a suburban style where houses are on 0.25 acre lots and there's only maybe 15-20 feet between houses then I feel my concerns are legit.
You could say that having homes that depend on cisterns actually helps in firefighting efforts:
I volunteer with our rural, island-based fire department. The more populated part has 90% or more of the people, and is part of our coverage area. The larger part is more parks and forest, and sees regional coverage such as chopper- or truck-based crews, helicopters and so on.
Each of the engine trucks carries something like 1000 gallons of water, and is kept full. So are the tenders, which can dump into the "porta-pond" as in that video. The water supply team has a list of available sources of water that they can go to to keep that water flowing, but if there is nothing nearby, the round-trip time will get longer, and firefighters will have to leave the building until there is water available.
Wildfire fighting is very different, and much more focused on containing the edges of the fire by using natural fire breaks or creating new ones. (Think picks and shovels, heli buckets, and heavy equipment where available.) If there is a house or two threatened, maybe some sprinklers can be set up ahead of the fire. If the house is on fire, too bad, efforts are on what's ahead.
It's pretty normal in rural areas to basically not have a fire department for all practical purposes anyway. Yeah, they often have a volunteer fire department, but when your best case scenario response time is like 30 minutes, you're not gonna save structures anyway. That's not considering the wildfire risk at all.