I’m not an expert in the matter, but I’ve heard that modern wood frames are just as good as steel frames. If the fire is close and strong enough to ignite a wood stud, the steel stud would already fail. Though would love input from an expert here.
The material you're more likely to use for a home if it's not wood is concrete or brick with some steel added. Concrete and brick are very fire resistant, which would make it much harder for a building to catch, and so harder for fire to spread if the building doesn't catch. The reason our homes in the US aren't brick (anymore) is it's a very expensive/specialized job, but wood framing is easy in comparison and wood is cheap here (and we have a lot of lumber mills to churn out small standardized pieces)
The inside would of course burn eventually if engulfed in a slow-moving fire with plenty of fuel, because things ignite when they get hot enough (or turn to charcoal if there's not enough oxygen). But if you're lucky the fire will move past quickly or run out of fuel, so every little advantage helps.
Any sort of structure, wood or not, will withstand a huge radiant flux of energy before catching fire. Well, well beyond what will crispy fry a human, the siding may be charred, but it won't burn. Even wood siding tolerates a lot.
What lights houses on fire are firebrands - "burning crap from the sky." Trees, mostly, embers, other houses... that's what catches things. Typically it will light some small stuff near the house first, or in the corners of the roof (pine needles are a common enough fuel source). At that point, you've got a far harder problem - direct flame impingement. If you get to that point, you are usually screwed.
You can build fireproof roofs - I fully support pretty much anything in any areas requiring a Class A fireproof roof, which doesn't really mean much more than "being careful what you build, and not using wood shake." An asphalt shingle roof can often be Class A fireproof, and that tolerates a 2' x 2' bit of burning brand on the roof without burnthrough. The roof may not be in great shape, but an awful lot of "stuff on fire" can land on it, and if it's a properly constructed Class A roof, it won't penetrate to the building.
The landscaping around the building is a harder problem. Within 30' or so, it generally has to "not burn." This can be from design, or from sprinklers, or... whatever. If the landscaping within 30' of a house is on fire, the house is likely to follow. If you keep that from lighting, the house stands a pretty good chance.
... yes, this means that in suburbia, if the house next door is on fire, you're screwed. Don't live in such tightly packed spaces.
The next major problem are windows. If they fail, the house usually goes. They tolerate a lot, but in high wind storms, random debris can break the window, and then firebrands get in. Whoops. I would like to see some good studies on shutters, because they seem like the sort of thing that will make a very real difference on window breakage in storms, but they're not a thing anymore and probably won't come back.
But look at the debris patterns when you find the news articles of the burned out neighborhoods. Almost always, you'll see intact lawns and vegetation around a burned out foundation. It's not a "wall of flame" marching through the neighborhood - it's the firebrands, blown by the wind, that you have to defend against.
Unfortunately, when it comes to wildfires, when you've got things like 80 gusting 100, you're also just screwed. :/
Having grown up in hurricane land, this statement stood out to me. Why did shutters go away? Why won't they come back?
That's one of those damned good questions.
I have thoughts, but I'd really like to see some solid information on how prevalent they were, what their previous rationale was, and what accounts for their decline.
On contemporary houses, if shutters exist at all, they're all but entirely decorative. Frequently they're on the inside of a house.
In hurricane-prone regions, shutters seem as if they'd make more sense than repeatedly boarding-up and unboarding windows.
Note that in the case of wildfire, embers entering into attic and crawlspace areas is a larger threat than direct radiant-heat compromise of windows, though ignition of interior furnishings (especially curtains or blinds) by radiant heat does occur. Still, window and other structure penetration shutters seem as if they'd be a potentially useful addition.
See this IBHS wildfire structure ember test video: