Are you sure?
You're right, not each toolmaker, or user, will develop on the time scale we've seen so for.
And, it might seem that just because each precursor or prototype doesn't develop, doesn't mean the the root from which they sprung wasn't bound to develop higher technology. An abacus isn't all that different from a stick, takes a bit more brain.
Precursors and prototypes may not all develop, may not die off, may not advance.
And the root may be doomed to develop egos, and technology.
Arf