First appeared in Asimov's.
The probably plays into readers' affections for New Worlds, a British magazine with multiple reincarnations--most famously with Michael Moorcock at the helm, captain of the New Wave. Unfortunately, the current zine appears to be in its death-throes with no submissions, registration required to view anything, and difficult to retrieve lost passwords. Ah, technology. So wonderful yet such a pain.
Beings from a different universe arrives via crosstime gate to investigate a spaceport and other technologies. However, they are immediately arrested. The different Earth beings discuss trading technologies, but not their most valuable. Stalemate.
*spoiler* The crosstime people exit and blow up the gate, thinking the other more powerful with access to alien technologies. The faster-than-light crowd is jealous of the zero-time travel....
It's hard to tell how much this tale is a tribute to that magazine, but there is a nice contrast between high technologies--both deathly afraid of the other's technology thinking the other superior. The grass is always greener. But they both decide to pursue technologies they now know is possible