Yes, I get that. I have a solid enough mental model on why starship designs might last as long as they do on screen.I'm fine with mental gymnasting the economy issues, as long at said gymnastics actually try not ignore the spirit of the moneyless economy concept and paint several characters as liars and hypocrites. I certainly have a solid enough mental model how I can see it working and fitting most of the evidence seen on screen well enough.
Why one is OK and the other is not amuses me.