A 30 minute window of operation severely limits the usefulness of the idea. I think Musk did the idea a disservice by focusing too much on SF-LA and the comparison with the California HSR project. Which made the Hyperloop come off as romantic as a 30 minute elevator ride, rather than something revolutionary.
If I remember correctly he said it would be feasible for long distance (>1000miles) but fast air travel would probably be more efficient at that point.
"The Hyperloop (or something similar) is, in my opinion, the right solution for the specific case of high traffic city pairs that are less than about 1500 km or 900 miles apart. Around that inflection point, I suspect that supersonic air travel ends up being faster and cheaper"
I don't think there's any sort of real limit at 30 mins. Pushing it up to an hour is still fine without having to seriously address the 'what about the bathroom!" issue. And you can go quite a way in an hour at that sort of speed.
There's also the 'passenger plus' variant. If it can take 3 cars it can certainly fit a bathroom :)
But again, I'm pretty sure they if we can surmount the rest of the barriers we can solve the toilet one...
