That's the fun thing, since we have only observed a single advanced civilization, and that one only indirectly through archaeological evidence, there's no hard facts to be had! We can only make guesses. We don't know what is and is not required to make an advanced technological species, and we won't have any answers until we meet another one to compare with.

AI is not important at all. Just make things more convenient, but is completely unnecessary.

Check back in 5 years. This is going to age poorly.

The reason is that, despite what many think, AI actually is able to create novel ideas and solutions. That's why AlphaGo was so important; it couldn't beat the world's best Go player just be being a fancy autocomplete and a big processor. It had to create new discoveries and then use them effectively. That was the turning point. It's been a decade of improvements since then, and AI is already making discoveries we couldn't have made without it. The impacts are already here and in your world, you just haven't recognized them as such yet. But in a few years it will be undeniable to even the most uneducated observer, since changes that could not be possible will be present in every person's life as the effects ripple out across basically every industry.

In no timeline nor carbon-based universe does GP's comment age poorly.

I am a bit skeptical but cautiously optimistic about AI “creating novel ideas”, if we are using “create” pedantically. Any interesting examples?

Those math proofs from a few weeks back seem plausible.

It looks like you've already done so with the order of the sequence that you used.

Arguably they're all fire -- requiring/involving forms of combustion.

(Well, debatable about agriculture, slash'n'burn wasn't the only form of it, but it was common for land clearing at least... all we have now is one that involves combustion engines, though...)

Nuclear weapons and the control structure around their use and fossil fuels and the C-corporation and what it optimizes for will probably turn out to be more important to the long-term future of humanity and it's civilization.

Fossil fuels are another feature like fire. One of the leading theories is that the availability of extremely energy dense fuels is one of the primary reason we were able to industrialize, and that without those fuels industrialization would be vastly more difficult if not impossible.

Personally I disagree with 'impossible', but it would definitely be harder. There's a pretty good argument to be made for leaving significant quantities of fossil fuels in the ground for the next civilization. If we wipe ourselves out, whoever comes next is going to very badly need those fuels to rebuild an industrial base.

There were copper & bronze age industrial sites. Esp Tin & arsenic bronze smelting sites. Complete with child labour, open pit mines, assembly line style processing, and heavy metal poisoning. E.g. Semiyarka, in present day Kazakhstan, ~1600 BCE. You can still see the environmental damage to this day from the air.

Romans had industrial processes, too, for things like fabric / laundry cleaning.

What's new in the 18th/19th century is full-on mechanization of industry. And the wage labour system to make it possible. Accompanied by acts of enclosure etc to drive the peasantry off the land and into factories. Also the mechanization of agriculture that went with that.

AI hasn’t taken its final form yet.