Satoshi Nakamoto on blocksize:
While I don't think Bitcoin is practical for smaller micropayments right now, it will eventually be as storage and bandwidth costs continue to fall. If Bitcoin catches on on a big scale, it may already be the case by that time. Another way they can become more practical is if I implement client-only mode and the number of network nodes consolidates into a smaller number of professional server farms. Whatever size micropayments you need will eventually be practical. I think in 5 or 10 years, the bandwidth and storage will seem trivial.
Long before the network gets anywhere near as large as that, it would be safe for users to use Simplified Payment Verification (section Cool to check for double spending, which only requires having the chain of block headers, or about 12KB per day. Only people trying to create new coins would need to run network nodes. At first, most users would run network nodes, but as the network grows beyond a certain point, it would be left more and more to specialists with server farms of specialized hardware.
The eventual solution will be to not care how big it gets.
But for now, while it’s still small, it’s nice to keep it small so new users can get going faster. When I eventually implement client-only mode, that won’t matter much anymore.
The current system where every user is a network node is not the intended configuration for large scale. That would be like every Usenet user runs their own NNTP server. The design supports letting users just be users.
It can be phased in, like:
if (blocknumber > 115000)
maxblocksize = largerlimit
It can start being in versions way ahead, so by the time it reaches that block number and goes into effect, the older versions that don't have it are already obsolete.
When we're near the cutoff block number, I can put an alert to old versions to make sure they know they have to upgrade.
The threshold can easily be changed in the future. We can decide to increase it when the time comes. It's a good idea to keep it lower as a circuit breaker and increase it as needed. If we hit the threshold now, it would almost certainly be some kind of flood and not actual use. Keeping the threshold lower would help limit the amount of wasted disk space in that event.
Bitcoin users might get increasingly tyrannical about limiting the size of the chain so it's easy for lots of users and small devices.
I’m sure that in 20 years there will either be very large transaction volume or no volume.
