There is no value without liquidity. i.e. (to trow a bone to the Austrians) If there is Bitcoin that becomes permanently illiquid its value is transferred to all other Bitcoin which may become liquid.
In that sense, yes. How much liquidity is necessary remains an open question, though. I offer that the relative amount of liquidity necessary for Bitcoin to thrive may be less than many other instruments.
But there is a risk inherent to the design of Bitcoin that, being a receipt, only has value in relation to what it is transacted for. And it only has value to you if you control either the receipt or the object being transacted. This means that it becomes money only when it obtains a generalized value, such as when you are holding it in a system of exchange and not via your control of keys to access the blockchain. It really is a critical distinction on what level of the hierarchy of the abstraction of transactions you control it, as each level has a distinct risk profile. The design is that it is a receipt and not money. It only becomes money when a generalized value is assigned to it, instead of it simply proving that specific transactions have occurred.
The next stage in the evolution of Bitcoin would be to maintain control of the actual keys while binding the receipts to an exchange value, therefore making them money. Right now you only have control of receipts, or actual objects transacted for, and it is only for that exchange, and that exchange only that imparts a transitory value to those receipts. Held in an exchange, for instance, there is a nomic value imparted to your Bitcoin because it is potentially liquid in that exchange which is trading at a nomic value. But then, in that case, you only have nomic control of a generalized Bitcoin and not actual receipts. The proof of this is that if you wish to obtain actual control of them the exchange would have to issue new receipts to you via its access to the blockhain.
The bolded section is key, particularly in reference to exchange value. It's essentially the Ripple concept, if I understand you correctly. I don't think it's the only possible next stage, though. It may turn out to be a situation where that system handles the majority of transactions, yet the common platform is Bitcoin.
Assume an environment, something along the lines of
Berlin's Kreuzberg, where Bitcoin can be exchanged directly for goods and services that are
denominated in BTC. There is no longer any requirement to participate in a traditional banking system: the Bitcoin network
becomes the exchange, displacing other units to establish itself as numeraire. As foundation, exchanges would extend Bitcoin, not the other way around.
With sufficient adoption and usage, there is little need for exchanges; they may be mostly a temporal concern during such a transition. It is the same issue that gold proponents push, suggesting that the dollar and euro might be measured in terms of gold grams rather than gold being measured in terms of dollars and euros; just a flip in perception. The exchanges might eventually have to shift gears to become gateways not so much for different currencies, but different asset classes, both financial and real.