Lets do some math. Tourist season in Croatia starts in May and ends in September. Thats 5 months. If the villa can host 8 guests and if the price for one night will be around 150$ per person thats 1200$ per day. 5 months = 150 days. Of course its not gonna be full all the time so let's say its gonna be full for about 120 days. 6 villas x 120 days = 720 days.

720 days x 1200$ = 864.000$
The guests will also spend some money on different rentals.
One season with 6 villas = 1.000.000$
500.000$ goes in gold and the other 500.000$ goes for next new villa. So every 2 years there will be new villa automatically.
Thats just my example. I hope that I didn't right something wrong.
And one another important factor. All Xaurum spent for renting the villa and other stuff goes to burn. So every year less Xaurum but more gold.