RocketDad's Ten Rules for Plausible Spacecraft Design:

[tilt]

great list ... I have a note to nr. 7 - as we move forward in time and space travel becomes normal, so will the prices to create spacecrafts also get lower (just like cars), however - this doesn't mean I disagree with your conclusion, cause just like cars you would still build as compact and light as possible to save on material etc. Extreme luxury products except from this of course - cruise ships for instance will probably have great big halls with all the bells and whistles then can push in and for which people pay ticket prices that would bankrupt a small country

[Aval Penworth]

On point 7. I'm with Tilt. There was a heck of a lot or reasearch done to get the ISS up and running. A lot of money was probably spent on finding out what doestn't work. In the future that money doen't need to be spent again. They know how to build a cost effective space craft. So there will probably also be room for mega yatchs so the Bransons and Trumps of the future can flaunt them.