TheNiceOne
Emperor
Quandary, I think I understand...
Anyway, just to make one more argument for why I think it should stay as now, regarding the cost of luxuries/resources compared to empire size, and that is the balance argument.
The resurce/luxury system is already heavily unbalanced in favour of the large empires. If you're a small empire, then the chance of having oil inside your borders is quite slim, and you cannot expect to have more than a couple of different luxuries. If you're a biggie, however, you'll most likely have several oil sources and 5-6 different luxuries.
And as we all now, one single oil source is enough for the bigge - so not only does it have a higher chance of having oil, but it gets to use the oil much more effectively as well. The same goes for luxuries.
This unbalance is taken away when a civ has to buy its resources, a biggie must pay proportionally to its use both for a luxury and a resource, but its still unbalanced since the biggie has to buy a lot fewer resources, and get to use all respurces better.

Anyway, just to make one more argument for why I think it should stay as now, regarding the cost of luxuries/resources compared to empire size, and that is the balance argument.
The resurce/luxury system is already heavily unbalanced in favour of the large empires. If you're a small empire, then the chance of having oil inside your borders is quite slim, and you cannot expect to have more than a couple of different luxuries. If you're a biggie, however, you'll most likely have several oil sources and 5-6 different luxuries.
And as we all now, one single oil source is enough for the bigge - so not only does it have a higher chance of having oil, but it gets to use the oil much more effectively as well. The same goes for luxuries.
This unbalance is taken away when a civ has to buy its resources, a biggie must pay proportionally to its use both for a luxury and a resource, but its still unbalanced since the biggie has to buy a lot fewer resources, and get to use all respurces better.