I expect that when the first caveman floated across a river on a log, all the local pundits derided the whole thing because they didn't see any quick ROI on it. Of course they were right, and maritime navigation never did the human race any good. Right?
If we could go back in time to when railroads were first invented, I'm morally certain there were the same sort of nay-sayers around pointing out many difficulties in using railroads:
High expense of acquiring land right-of-way
High cost/availability of fuel
High cost of laying track
High cost of maintaining/replacing track
Many, many water/terrain obstacles and high cost/time taken to build bridges
Mountains! Many are too steep to go over, and it would cost a real packet to try to make a tunnel through one, if it were even possible, which it clearly is NOT.
Yet all these obstacles, and many others, were overcome by genius engineers. Hyperloop will probably have some of those working for them, too.
Some of the the objections to hyperloop seem questionable to me. Even I can think up some at least plausible answers to them. I expect real engineers could do a lot better than I can. So let's look at some that I can think of answers to:
Low passenger volume due to each capsule operating separately. Why couldn't you hook multiple hyperloop capsules together into a long, uh, TRAIN? Just because they can operate independently doesn't mean they must.
Stations: These would be open air platforms, just like train stations. Several hundred passengers could board/leave the train in one minute.
Time to evacuate the tube: Once loaded, the train would go into an airlock. You could have many air tight doors. The train would go into the tube and right up to the door leading into low pressure. The station would then close the door closest to the rear of the train, then open the "front" door. Since the train would fit fairly closely into the tunnel, and little space would be left behind and in front of the train, the air volume inside the "airlock" would be insignificant and just vented into the tunnel. (Tunnels would need to have vacuum pumps running all the time, anyhow, because of leaks, etc.)
Braking: normally electromagnetic, but in an emergency (say, a power failure), the train would drop, and the guides would contact the rail. You'd get metal-to-metal braking just like trains use. Not sustainable for constant use (at least, not without a lot of maintenance), but it works fine in an emergency.
High G forces: Why use high G's? Right now they're playing around and showing concepts. Yes, it accelerates fast. But in real use, except for emergency braking, the acceleration and deceleration could use forces no higher than than passengers normally encounter in an airliner.
There are always issues, questions, and sometimes serious problems to be solved in any major endeavor. But these can often be overcome.