note that in the future a "consensus" process can issue more of them.
No, that's not right. If it was possible for the consensus process to alter account balances arbitrarily the system would never be accepted. One of the invariants of the Ripple system is that XRP cannot be created at all, and that the genesis ledger entry (first ledger entry) starts a certain account (to which the founders hold the private key) 100 billion XRP.
The goal is for them to NOT be scarce
Also incorrect.
XRPs must be scarce to deter transaction spam. This is
directly from the developers of the system.
Why would folks give XRPs away to keep them scarce? The ripple community's goal (as envisioned by the creators) is not for XRP to be a scarce commodity, but merely for them to be valuable enough that it isn't easy to spam the whole network with new transactions or new accounts.
"Valuable enough" means "scarce enough to have value."
So don't expect XRP to skyrocket in value.
XRPs function ideally as currency, and one could argue they function as a reserve currency. In some ways they could be better than Bitcoins.
Like the founders keep saying - they're like stamps to let you exchange other currencies.....
No, that's not what they are saying at all. OpenCoin's business plan is to "hold XRPs and hope they go up in value." This is a direct quote (see above).
You need to review the statements that have come from developers of the system again, I think that you are not looking at the big picture.