> The 21st? The iPhone? Meh.

Only 20 years in (or is it 'already 20y in'?), and there's already reusable rockets, CRISPR, 3D printing and the combo deep learning + astonishingly both powerful and affordable CPU/GPU/TPU.

I would say this is already an interesting century, invention-wise.

Also, one could argue that the 21's internet is not the same as the 20's, in which case modern, cheap and massively deployed internet can be classified as a 21st great invention.

But we're splitting hairs. Centuries are an artificial construct. Measuring pace of change by such a crude method makes no sens to me.