As was pointed out, the ancient Assyrians may have had an "electric battery", but was it anything more than a trick? Were they making flashlights to connect to these "batteries"? No. And the Chinese invented "gunpowder" many, many years before somebody packed it onto a tube, shoved in a burning fuse, and threw it at an enemy with a shout of "Eat This!"
Some of the low TL items surprised me a little at first (like rockets), but thinking about it, this does represent the earliest sustainable level for those Technologies rather than when they became popular on Earth. If someone had attacked ancient China with a stick of dynamite, the Chinese COULD and WOULD have developed an "Eat this!" weapon in response.
Star travel creates the input and incentive to NEED these technologies earlier than the Earth did. As pointed out elsewhere, the Victorian Era could have built a supertanker sized ship, but had no practical need for one. A Roman Railroad economy grown to Early Industrial Age technology might have a need for a Victorian Supertanker.
Imagine how Earth History would have changed if the Roman and Chinese Empires had met, merged and survived with Roman Engineers and Chinese Bureaucrats seeing the need for and creating a Transcontinental Railroad linking the Atlantic and Pacific Oceans and shortening communication time across the super-empire. It would have been a huge project – like the Great Wall or Roman Highway network – but not impossible and potentially necessary.