I do storm spotting for the National Weather Service. While most of my training on lighting is about lightening
safety, I have done further studies into lightening strikes.
In short, while lightening rods may work, there's no guarantee they will, even if you have them installed. This is simply because of how lightening works. A typical cloud-to-ground bolt is a series of steps, starting with a leader, that moves in segments. Each segment is about 150 feet long, and they can branch like a tree (you've seen this in photos). It continues trying to find the path of least resistance until it's 150 feet from something on the ground. At this point an upward leader can occur (say from a house) and make a connection. This is the lightening strike.
The 150 foot segment is important because it means the ground could be hit and something very tall near it could be missed entirely if it's beyond this limit. It also means lightening can strike very far away from a cloud because of the branching effect. While something tall (like a lightening rod) has more potential to be hit, it's not a guarantee. It's possible the upward leader could come from the edge of your house instead of the lightening rod because it's closer to the final 150 foot segment than your lightening rods are. The distance matters in the end, not the height (though tall object have more potential to be hit because there's less of them around as the bolt works its way down to the ground).
Also keep in mind that most lightening strikes don't start fires like what happened to your neighbor. For that to happen you need many pulses of lightening on the same spot for it to usually get hot enough. Everything happens so fast in lightening but a strike can be one stroke, or as many as 20 in a row as the electrical energy dissipates. You've probably seen this if you've seen a bolt flash and strobe quickly as it strikes. It's the later ones that are the problem for starting fires, because they keep the energy on a single spot for a long enough time to cause combustion.
We've had a couple lightening strikes in our neighborhood on houses that have caused fires. One was surrounded by a grove of trees much taller than the house (which should act as natural lightening rods). Didn't matter. All I can say is if it makes you sleep better at night, look into it, but at the end of the day, whether you get hit or not basically comes down to dumb luck. And having rods installed is no guarantee that they will be effective. Mother nature doesn't care.
By the way the material of your roof doesn't matter. Lightening isn't attracted to metal. It's attracted to whatever is closest. Lightening rods are metal because they allow you to move the electricity after the hit away from the structure to the ground (path of least resistance). That path may not mean you steer clear of damage. If you get hit, you are likely to blow out all the electronics in your house regardless. Though obviously that's better than a fire.
If you want to see what a lightening strike looks like in super slow motion, here's a good example:
https://www.youtube.com/watch?v=dukkO7c2eUE
Note how it branches in tons of different directions as it travels down, and how it looks like a step pattern and a tree. Also notice how when it finally hits, all the branches that didn't make ground contact get "sucked in" and are now part of the main lightening strike. That's how it works. All of those potential other branches never actually reach a target. Instead they become part of the flow with the branch that hit. This is why I say a lightening strike is a bit of dumb luck. For every place that gets hit, there are dozens of others that could have, but didn't, based on geography, topology, surroundings, what have you.
. . ).
