+1Build cost = $70M
Real Estate increase in Mumbai = 15 times
Expected market value = $1.05B
Honestly I think it's a bit of a stretch to say that because the market when up 15 times that this place is worth $1B. It's worth the price that someone else is willing to pay so the question is; is there someone else on Earth willing to pay $1B for this home?
... a floor dedicated to servicing your cars is tempting though....