Remember that each of the houses economies went through their infant years in isolation of each other. This means no comparative advantage and few things in the way of economies of scale. Freelancer also doesn't make use of the self replicating machine as far as I know.
I would not say that starfliers are as complex as cars in the future. They would be as affordable, perhaps, but affordablility does not indicate complexity or lack of. This can be seen in the electronics market, which is ungodly complicated in terms of production processes and technological principles, but quite affordable for the lay man who thinks Norton is the best.
Remember how a battleship/carrier is built today. Think about how much larger their displacement would be once they don't have to float in anything anymore. How many resources is this? What about support systems like air and food storage/recycling? Energy systems, weapons, shields, whatever the space version of radar would be and so on. It's pretty complex to build a ship now...
