People are confusing XRP (ripples) with Ripple. All you need are a few XRP to use Ripple (300 to get started and 0.00...01 to make a transaction. ie they are not used as a store of value.
It looks like they have been intentionally designed as a bad investment to discourage people using them as a store of value.
The value of the Ripple network is not connected to the Market Cap of the value of XRP since you can still make ripple transactions even if they are worthless.
This assessment is questionable. You do know that XRP is the safest assets inside the ripple network, don't you? Not to mention the fixed cap. XRP certainly has the potential as a good store of value.
Although that's assuming the initial distribution is complete. Before that happens, XRP may very well keep going down in the market.