[GeneralMayhem]

I can think of a couple more major disadvantages they have.

3. Living underwater. Fire is the easiest way to extract energy from raw materials, and there's no real substitute. On land, there's a lot of local, controllable dynamism, but when you put things down they tend to stay where you put them, at least on short timescales. Water is exactly the opposite: lots of changes you can't control, but no way to get a lot of energy all in one place. Dolphins would have a hard time developing technology for the same reason, even if they had the dexterity.

4. Not being apex predators. This is part of the short lifespan problem, but I think it goes beyond that. Not many animals are going to mess with a human if they can help it, which means that it didn't take much for us to get to the point of having some free brain cycles to spend on improving things. An octopus is comparatively small and squishy, and shares an environment with comparatively more large and toothy carnivores, which means that even when they do manage to survive for more than a couple years they're doing it by spending most of their time eating and hiding.

[Hithredin]

However the apex predator negative side can be compensated. Human are pretty weak, but still our species made it, certainly thanks to social behaviour

[chewxy]

3 seems to be the an argument from the anthropic principle. Oxidation happens in water too, in different forms. Perhaps not as rapid. I would imagine someone from Mon Calamari would have came up with a completely "easiest" way to extract energy.

[nabla9]

> Perhaps not as rapid

The point of fire is rapid oxidation that provides enough heat to melt metals.

[GeneralMayhem]

Slow oxidation underwater isn't useful for anything, though. You can't use it to do work without a lot of additional technology to capture energy over long time periods.

Set aside what we know about human technological progress. You need some energy source to be the base of your technology pyramid, and it needs a few properties: it needs to be naturally occurring so that you can discover it by accident; it needs to be controllable or predictable enough that you can use it selectively; and it needs to be fast/intense enough that you can transform materials without massive time investment. What do you pick? On land, you have fire, flowing water, and, at a stretch, the muscles of large herbivores. Underwater, you have... ???

Also, that's not what "anthropic principle" means.