The idea here, I think, is that Dragon requires a heavier rocket - Falcon-9 - that the Soyuz does. Soyuz flies on a rocket with payload around 7500 kg, while Dr

The idea here, I think, is that Dragon requires a heavier rocket - Falcon-9 - that the Soyuz does. Soyuz flies on a rocket with payload around 7500 kg, while Dragon flies on a rocket with payload, according to Wikipedia, "15600 kg when landing". So it's either a heavier spacecraft or an under-use of a rocket. Not that such use would be particularly bad - from a point of view of standartization of launchers, for example, or taking into account that F-9 has a reuseable first stage, it makes more sense. However by payload mass the Soyuz looks more optimal.