it will be possible for all these mini robots to get together and create a collective intelligence between them
With all due respect ...I don't think so.
How does that follow?

our world is changing rapidly and 2099 will be more different than 2000 in comparison with 1999 and 1900.
That is an incredible...understatement.

The world has changed more (technologically) in the last year than it has in the last century.
A century from now is literally un imaginable. The future isn't what it used to be.

No one predicted the internet...no one predicted the blockchain. Hell no one anticipated the unintended consequences of a car in every garage (or televisions in every house) and the concept of almost everyone carrying a supercomputer in their pocket, which incidentally could also communicate...was inconceivable forty years ago.

the meshnet, the iridium system both currently under construction..will make it even MORE inconceivable.

let's not talk about Utility Fog...mindblowing.
or graphene...or augmented intelligence, direct neural interfaces, full sensory augmented reality....and many, many more technologies...in the lab right NOW!...

did I already use the word inconceivable

ahem.

sorry..

I agree with your fundamental concepts...but in my not so humble opinion you are being MUCH too conservative.