Occam's Razor is sharper than Hanlon's. Elon clearly doesn't truly believe that Hyperloop could work. Hyperloop's intention being the disruption of working mass transit is the simplest explanation.
> Remember GM trying to scrap public transport projects?
I'm assuming you're referring to the GM streetcar conspiracy here. What GM actually did was try to monopolize the supply of buses--which is still a form public transport. They also did buy out several streetcar lines, but the streetcar systems they bought were already bankrupt or on the verge of bankruptcy. There's no real difference in the trajectory of streetcars in the cities which were bought out by GM and those in the cities were they were not bought out.
Tesla competes with gas cars, not trains.