On 27 January 2017 15:53:02 GMT-08:00, Andrew Johnson via bitcoin-dev <bitcoin-dev@lists.linuxfoundation.org> wrote:
>I'd also like to point out to Luke that Satoshi envisioned most full
>nodes
>running in data centers in the white paper, not every single user needs
>to
>run a full node to use bitcoin.  Not to present this as an argument
>from
>authority, but rather to remind us what the intention of the system was
>to
>be(p2p cash, not a settlement layer only afforded by the wealthiest and
>largest value transactions).  That a lot of people want to continue to
>move
>in that direction shouldn't be a surprise.

Satoshi also thought that SPV clients would be able to use fraud proofs (called "alerts" in the white paper) to detect fraudulent behavior by miners, and thus not have to completely trust those nodes in those datacenters. Unfortunately it turns out that fraud proofs are both a very difficult engineering challenge to implement, and also offer much less security than once thought. In fact, as per Satoshi's vision, SPV clients don't currently exist; what's called SPV isn't what Satoshi was envisioning.

Of course, this wouldn't be the first time that aspects of Satoshi's vision for Bitcoin turned out to be wrong: the white paper also refers to the "longest chain" rather than most-work chain, something that had to be fixed in what's technically a hardfork after Bitcoin's initial release.