Centrally controlled trains are still required to be spaced out by their stopping distance. The only way this or hyperloop will do better than trains is through regulatory arbitrage.
Quite the opposite: the requirement to be spaced out by their stopping distance is regulatory arbitrage; if the design was "it might, in corner cases, crash and injure people, but who cares, they knew the risk", you could run trains far closer together (which happens all the time in manually controlled streetcars: tailgate the other tram and pray the guy in front won't slam the brakes).
Regulatory arbitrage is when you profit from a difference in regulations. If someone could figure out how to run a train but have it regulated as a car (with car-like safety properties) they would be able to run an extremely high-capacity service; I suspect this is Musk's gameplan.
