Obviously. But even in a game they can represent things a little more plausible. Sure, a big ship has more mass so logically it would be slow yet MWD and other factors are added to the cost of the ship. It’s like you buy a car but it only has a grassmower engine and you have the engine on top of the cost of car. Haha!
Ship cost goes up to several billion isk. What do you get? An empty hull. No engine worth a damn, nothing.
Did the astronauts go up in space without a working oxygen maker? Did they have to buy and install the engine themselves? That was 1969. And they’re telling me New Eden is 23358 in the future? Haha!