When looking at things like mechanization and the productivity increases from around 1880 to now, you took an economy from around 10 billion a year to 14 trillion. This involved mechanization and digitization. We live in a world that someone from 1880 really couldn't imagine.
What I don't know how to answer (or at least search properly) is how much investment this took over that 150 year period. I'm going to assume it's vastly more than $7 trillion. If $7 trillion in investment and manufacturing allowed us to produce human level+ AI then the economic benefits of this would be in the tend to hundreds of trillions.
Now, this isn't saying it would be good for me and you personally, but the capability to apply intelligence to problems and provide solutions would grow very rapidly and dramatically change the world we live in now.
Sure, but right now that "if" is trying to do 7 trillion dollars of unsubstantiated heavy lifting. I might be able to start creating Iron Man-style arc reactors in a cave with a box of scraps and all I ask is 1 trillion, so you all should invest given how much money unlimited free energy is worth.
The words "just" and "surely" are doing so much heavy lifting here that I'm worried about labor-laws. :p
If scaling up was "just" that easy and the next step would "surely" begin in the exact same architecture... Well, you've gotta ask why several billion general-intelligence units made from the finest possible nanotechnology haven't already merged into a super-intelligence. Or whether it happened, and we just didn't notice.