"we're ±100 years from a development that results in (let's say) a 20 year bump, before those 20 years are up we will have accomplished a 60 year increase, within the following 60 we'll have managed to tack on 180, etc."

Predicting the future by extrapolating a trend without bound, that's kinda like the singularity. I have trouble with this sort of thinking. It's a little too pat, a little too wishful, requires a little too much reliance on faith. Things are never that simple. You can't just find one screw and keep cranking on it indefinitely. Progress relies on the occasional blacksmith[1].

And this is good. It helps social mobility. I have a hard time imagining a metric that wouldn't entrench a tiny set of haves if it grew without bound. Monotonic progress perpetuates the status quo, like trees stunting the ground around themselves. To avoid it requires periodic creative destruction. Ends of eras. The saturating of metrics.

(If I could still edit my original comment I'd replace 'weird' with 'interesting/weird'.)

[1] http://en.wikipedia.org/wiki/Johannes_Gutenberg