... that the rocket will rely mostly on liquid hydrogen and liquid oxygen fuels. Those don't sound like petroleum to me, but I don't really know much about them to be honest. But I would imagine that the lift-off fuel would indeed be likely to limit the mass that can be carried.

As for why it's a gigantic space cylinder, I would imagine that's because that basic design is the most efficient and aerodynamic for pushing an object into space and breaking the planet's gravitational pull? What would you like to see instead? (That's not snarky, I'm just curious what you think would work better. )

But yes, it is disappointing that we've progressed so relatively little over the last 40 years when it comes to spaceflight, a snail's pace compared to other technological areas. But I find it encouraging that they still see Mars as their goal, and seem to feel that it's reachable by 2030. Even if that probably means 2040 or later in reality. I'm happy that there is any progress toward that goal, even if it's slower than it should be.