Technological evolution, like biological evolution, follows a pattern of punctuated equilibrium. Long periods of stability give way to surges of rapid progress when the environment changes to create a need for innovation. And not every set of circumstances calls for the same type of innovation.
And progress isn't always in a single direction. Societies can turn inward as well as outward -- see, for instance, Ming Dynasty China, which explored the world using fleets of the most advanced oceangoing vessels on the planet, but then abandoned exploration altogether and lost interest in the world beyond its borders, because its rulers felt they already had everything they needed. I've always taken Jaro's line to mean that Bajorans spread their civilization to the stars during an earlier space age, then retreated to their own world for millennia, then began turning outward once again. After all, modern Bajorans are a spiritual people, which suggests a focus on more inner-focused and philosophical pursuits rather than material and technological ones. (Cf. the Deltans: According to Roddenberry's TMP memos, Deltans long ago abandoned their space age when they chose to turn inward to more spiritual pursuits, and they see human starfarers as a reminder of their "primitive" past.)
Anyway, Picard's "standing erect" line cannot be taken literally, because it's based in deeply outdated assumptions about hominid evolution. Hominids were standing erect as far back as Australopithecus afarensis four million years ago -- very, very long before anything that would be called a human being. That means Picard's line is basically gibberish. If we assume he meant "before human beings evolved," that could mean anything from 500,000 years ago, when Homo sapiens diverged from H. neanderthalensis, to 200,000 years ago, when anatomically modern humans first appeared.