I mean, of course it is important to know where stuff comes from, we're talking about ~10 days and a few hundred transactions here though, not about how Ripple works since then.
Somehow I get the impression you already know this, but let me spell it out for anyone who doesn't: it only take
one unaccounted for transaction to allow for trillions (or more) in unaccounted for currency units, because it's all only data.
In Bitcoin yes (since it is based on previous outputs of transactions), in Ripple (which is based on balances) this is not true.
The bottom line is it's
not possible to verify the number of Ripple currency units in existence, in contrast to Bitcoin. You've already expressed as much:
It would be very unexpected to see that more than 100 billion XRP existed prior ....
I don't care if the system is based on balances, transactions, or lunar eclipse events. If ordinary people can't mathematically verify for themselves the number of units in existence they should be wary of investing anything into it.