As I said, we should see some of these "transitionals" still hanging around.
Why? The fossils are proof that they did exist. That's all that evolution requires.
Why did all of those die out?
The leading contender is us. Evidence points to H. erectus and H. neanderthalensis going extinct due to competitition with H. sapiens. The species that went extinct after modern humans emerged were our cousins, and not our direct ancestors. Again, I don't understand why you require sister taxa to be living today in order to accept the transitional forms that are found in the fossil record.
Of course, we could also go back to our common ancestor that we share with our gorilla cousins. If we trace our lineage back to that shared ancestor, there is a fork in that tree. One of those forks leads to living chimps. Chimps are the very thing you are looking for, a living branch of the lineage that led to us from our common ancestor shared with gorillas.
Please forgive my ignorance, but what is the difference?
Do you understand the difference between your cousins and your grandparents? Chimps are our cousins. We are not their descendants or ancestor. They are not our direct ancestor or direct descendants. We share a common ancestor, our grandparents in the analogy. Our grandparents are neither us or our cousins. In the same way, our shared ancestor was neither a human nor a chimp.
Then why are we still seeing viral bacteria get stronger and more resistant? Or do you feel this is incorrect?
Firstly, there is no such thing as viral bacteria. Viruses and bacteria have less in common than flies and elephants.
Bacteria evolving to their environment has been happening since there were bacteria. They will continue to better adapt to the new environments that humans have created. That is how evolution works. That doesn't make them "more" evolved than a bacteria that does not infect humans. All bacteria are either adapted to their environment or adapting to a changing environment.
I'm admittedly at a loss...is it human brains -vs- chimp brains, or is it big human brains -vs- little human brains? I'm referring to the latter; it just seems like you're stuck on the former.
This is what you asked:
"At what point in the evolution chain from chimp to homosapian did one of those intermediates start speaking? Think of the complexity of speech. Why are we the only group of anything that can fluently learn to speak a (many of us more than one) language, and not just mimicry...I mean use of diction, syntax, word composition, sentence composition, meaning, inflection..."
Australopithecines are the hominid transitionals that had a chimp sized brain. They were at the left hand side of that scatter plot I showed you earlier. The plot shows how hominid brain sizes increased increased over time with respect to body mass. That is the reason that our lineage learned language, the evolution of our brains.