I had forgotten how early there were 100s of millions of mobile phones selling each year.

Yes. Mobile phones surpassed PC run rate before the bubble.

For at least a decade no-one in America understood this. Contributed to Nokia's complacency.

And their total dominance (at a deep branding level) in emerging markets.

It takes a lot to squander a lead like Nokia had. But Elop &WP persevered! (Android wasn't panacea but would have gone better than collapse)

And the poor quality of the dominant phones in the US market (which probably affected Apple's thinking too)

Wait, Nokia grew complacent because nobody in America understood this?

Yes. Americans had crap phones and didn't understand mobile, so how could any threat come from there?

Now I understand what you meant

By some measures, it's the most quickly adopted consumer technology in history

Though, as with most things, it's all in how you frame the question.