Probably a stupid question, but why don't we encase the (undersea) cable in some metal container or something so that it would not be so easy to break? Is it due to economics? Is the constant fixing in the end cheaper than making it hard to break, or perhaps it needs maintenance anyway often enough to make it a hassle?
You have to encase the entire length of the cable, which can be hundreds of miles, but the attacker only needs to attack a single spot. The nordstream pipeline attacks have shown that planting explosives on undersea infrastructure isn't exactly hard, so you end up paying an enormous price to add a knee-high barrier for a would-be attacker.
The other approach that can work in some areas is to use a plough to bury the undersea cable in a trench. This is much slower, more expensive, and damaging to the marine environment.
They are armored when they get close to land. But at depth they are not because of weight & economics. Even if a cable were armored for the full length - I'm not sure it would withstand an intentional anchor-dragging.
It would cost so much material. I think it would be more economical to just bury it. With an automated robot of course. It would also make it a hell of a lot harder for an attacker to locate the cable. But I don't know if these already exist.
They mention at the end that it makes it heavier and harder to deploy, as well as how rare it is that they get damaged.
But I think this is the point of the article - that we start thinking with “a wartime mindset”. Which is a shame, but maybe necessary given the state of the world.