AFAIR the paper was technologically sound to the first approximation; the objections were mostly economical (I'm ignoring people who missed that Hyperloop was not a vacuum tube design and went on ranting how infeasible it is).

Also, for a paper-only design, there seem to be plenty of activity involving people building actual hardware to test components.

Also2, from the first day it was known that Elon is not going to pursue Hyperloop himself any time soon; he threw an idea for others to pick up, and didn't promise anything. Judging him by not having built the Hyperloop by now is... insane.

Then there is the promise of taking humanity to "mars", which quite honestly, sounds a bullshit claim at this point. It wold have held more water, if they said it after making real tech breakthroughs (Ie not stunts like landing a rockets, which only guillable people finds magical because they were not tech savvy to know that it was possible with tech that is half a century old).

> It wold have held more water, if they said it after making real tech breakthroughs

Going to Mars is literally the only reason they're in the rocket business. Like everything behind their breakthroughs, which they had a few - including landing and turnaround times - is meant to enable the Mars mission. They've been explicit about this since day one.

> stunts like landing a rockets

This is not a stunt. It's the real, practical, working, cost-effective rocket reusability. For the first time ever. Not sure what do you expect; em-drive? Because SpaceX booster landing is exactly how a technological breakthrough looks like (as opposed to fundamental science breakthrough).

It's not so much a rocket company with a Mars objective, it's a Mars cult with a rocketry front operation.

Somehow, people get the idea that they're "not really serious" about the one driving goal that they've never deviated from.

The force of the idea of Mars keeps people focused on what really matters.

It's getting tiring, really - people seem to still believe they're bullshitting with Mars, even though it was the single constant thing about SpaceX since the very inception of the company.

Whether Musk gets to take humans to Mars or not remains to be seen, but in the meantime he's making a lot of progress that is going to be super useful to humanity.

Whether it was possible or not is irrelevant, what matters is that someone actually went and did it.

After all, the internal combustion engine could have probably been built in 1750 or so, but nobody did...