Yeah but that's just the cost of the island. Even if you built your home with your own two hands there's still the cost of all the building materials... and then the expense of getting all the supplies shipped there. What are you going to do for electricity? You'd have to go solar or wind.... either way... that's going to cost a small fortune. What about sewer and water? Unless you are planning on shitting in a hole and burying it and preying you find a fresh water spring that you can lug your water around you are looking at huge expenses in those areas too.
I'm guessing the real cost of buying that $1 Million dollar island and building a home with running water and power for yourself on it to be upwards of $10 million when it's all said and done.
Now... if you got 100 people to invest and build homes there... the cost of power and water installation would be shared and thus bring down the per house cost to a more reasonable number.
It's a nice fantasy to have.... but the reality of it... is something else altogether.