Housing as it is now isn't an auction, it's a lottery drawing, where the price of entry is refunded if you lose.

This isn't the best way IMO: a sealed-bid auction with a minimum bid based on lot size would have been better.

The amount of gil such a house-sale system would have removed from the game would have been staggering; there are plenty of people who could bid 200 million or more on house without breaking a sweat. And removing gil from the game results in deflation, which lowers prices of everything, and that benefits us all.