From the bitcoin dev mailing list quoting
Wladimir van der Laan:
The block chain is a single channel broadcasted over the entire
world, and I don't believe it will ever be possible nor desirable to broadcast all the
world's transactions over one channel.
The everyone-validates-everything approach doesn't scale. It is however
useful to settle larger transactions in an irreversible, zero-trust way.
That's what makes the bitcoin system, as it is now, valuable.
But it is absurd for the whole world to have to validate every purchase of
a cup of coffee or a bus ticket by six billion others.
Naively scaling up the block size will get some leeway in the short term,
but I believe a future scalable payment system based on bitcoin will be
mostly based on off-blockchain transactions (in some form) or that there
will be a hierarchical or subdivided system (e.g. temporary or per-locale
sidechains).
Thanks for quoting that! Wladimir's quietness in the public muck is as pronounced as his activity in the codebase. I never knew where he stood on this stuff. My natural guess would be that anyone who is bright enough to be such a prolific code contributor would immediately understand certain things like this, but...Gavin...
As someone who has worked on and designed data management systems, Wladimir's statement is so common sense to me that it shouldn't even need to be stated. I am aghast that there is so much dispute about it. A very strong hypothesis is that many people who have some technical skills are busying themselves with solutions which will be viable only by at least a scaling induced semi-failure of Bitcoin...and those who's technical and analytical skills are weak or non-existent are just expressing their inborn goober-ishness.
Sidechains not only soundly addresses the issue, but the two-way peg completely demolishes any economic concerns as well.
I agree, seems presumptuous if not reckless to take on the whole world only with bitcoin.