2/ Spark needs to be used as collateral to make . According to the whitepaper, there needs to be 2.5 for every 1 FXRP. Given that FXRP is the same price as , the price of Spark needs to be at least 2.5x the amount of XRP used in smart contracts.
If 10% of the 45 Billion supply is used for smart contracts, that's 4.5B XRP locked up. If XRP is $1 (for easy calculations) then you'd need $11.25B worth of spark (in ) to collateralize that much .