There are a number of ways of looking at this, which others have answered, but here's another:

The kinetic and potential energy of a 1 kg mass in orbit is around 33 MJ. The chemical energy of 1 kg of methane+oxygen propellant is only about 11 MJ.

Alternately, perfectly combusted methane-oxygen propellant has an exit velocity of around 3500 m/s. But you need about 7800 m/s to get into orbit.

Chemical energy is just very weak compared to the energy of things in orbit. It's really shocking that we can do it at all.

The result of this is that your vehicle is going to be almost entirely propellant. You simply can't just build a big, beefy rocket that's, say, only half propellant, with lots of extra safety margin for things that go wrong. Cars and bridges and things have immense margins. Airplanes, a bit less so, but still more than rockets. Rockets live right on the edge of what's possible, and as long as we use chemical thrust it'll always be that way.

Which isn't to say that rockets won't get more reliable. The Falcon 9 has had hundreds of flights since the last failure, and it isn't as optimized as it could be. But there will be a lot more failures before we get there.