Controls engineer here - no, that's pretty normal. I'm accustomed to automotive work, but I believe the electronics assembly lines are similar. The flexible materials handling stuff (connecting flat flex cables? Applying Kapton tape?) is indeed super impressive, but the timing is ordinary.
A sizeable 6-axis robot like those used here has a minimum cycle time of a second or two for the simplest possible "move in, place the thing, move out" operation. They're not ultralight delta or SCARA bots, they're about as fast as a human can control their arm. Also, there's a second or two lost while the pallets moves along and are parked at the multiple stations along the line, you want to design the system to maximize the ratio of useful on-station time to transition time.
The line is bottlenecked by the slowest process. You can make a slow station run in parallel - as in the photo at [1] with the 16 stations arrayed around the robot - but that adds a lot of complexity. I'd assume that their requirements were to accommodate up to ~8 minutes for burn-in testing at that station, and that by the empty stations, the software guys ended up only using 4 minutes. You can't make the whole line wait that long, so you spend the extra effort and introduce extra complexity by buffering parts there, but now your process has forked and needs to be merged again - really a pain for tracking suspect parts or tools. All that matters is that you unload each pallet before it needs to move on and replace it with a completed part.
Some stations may be doing nothing but running a 5 second electrical test. If there's some station that has to pick up a cable, photograph it, analyze it, contort it by rotating robot joints through large angles, plug it in, and get out of the way, that could easily take 10 seconds. Others may have a human who needs to keep up. Others might be heat-staking a plastic component and need time to blow on the stake until it cools enough to be unclamped. Others might have multi-headed tooling and can connect several different parts all at once. 30 seconds is a nice middling part-to-part value if you've got a few complex operations, a few human operations, and don't want heavy robots slinging your expensive parts around at high speed. I wouldn't have been surprised at a 10-second cycle time, but 30 seconds is still reasonable.
A final consideration is that you don't want an entire factory dependent on a single line. If you want to produce thousands of parts an hour, it's much, much better to have 10 identical lines that work at a 30-second cycle time than a single line frenetically thrashing to put out out parts in 3 seconds. If one line goes down, you still have 90% capacity, and can probably catch back up. If your single line goes down, you're in big trouble.
[1]: https://s3-ap-northeast-1.amazonaws.com/psh-ex-ftnikkei-3937...
