The UTXO set is actually bounded. The total amount of satoshis that will ever exists is
(21x10^6) x (10^8) = 2.1 x 10^15 = 2.1 "peta-sats"
...
I have thought about this bounding (mostly in the context of the current rather awkward/deceptive 'unspendable dust' settings.) I think that there is currently, and probably for quite some time, some big problems with this rosy picture:
- UTXO is changing in real time through it's entire population. This necessitates currently (as I understand things) a rather more sophisticated data-structure than something mineable like the blockchain...
If the block chain were bounded in the sense of what most users could process, you could potentially have serious problems because it would also perhaps open the possibility that users can also exceed that bound in their demand for coin divisibility. One of the reasons I am so big on micropayments is I believe that divisibility is scaling with computation scale. I also believe this is related (in a round-about manner) to the inexorable trend to maximum division-of-labor. I'll expound on this in the future, perhaps in the Economics Devastation thread.
I do believe the fundamental design error is requiring the blockchain to include transactions. (I am of course cognizant that many would dismiss that prior sentence as bizarre, n00b, insane, or what ever adjective you prefer)