Now, we have essentially 10 big mining pools that are the sole authors of the bitcoin block chain. How many copies of that chain do we need to serve, all over the world, in order for me to be able to verify the authenticity (that a piece of it I download, is of the real block chain out there made by these 10 mining pools) ? I would think that a few tens of copies that are publicly available are good enough. That my neighbour cannot have a server in his basement, is, just like before, no problem.
I can easily check, from the moment that I have access to any public repository of the entire block chain, that the small piece I need, is authentic, that is, belongs to the sole and unique chain that is out there, made by these 10 mining pools, like I could verify that the document I downloaded was cryptographically signed by one of the 10 authors of these documents.
(...)
And nothing is gained by having thousands and thousands of identical copies ; if, in order to have those thousands and thousands of identical copies everywhere, we cripple the system, we're totally out of our minds.
I vaguely, sort of, kinda see your point, but the simple fact remains that thousands of copies is more resistant to regulatory shutdown than 10. Thousands of copies is more resistant to bribery and corruption than 10. Thousands of copies is more resistant to any other kind of collusion, manipulation or attack than 10. Strength in numbers and such. The more distributed it is, the stronger it is. We'd be totally out of our minds if we trusted such a small number of people to remain honest when the incentives to be dishonest become inexorably more profitable over time.