In the meantime on another thread gmaxwell commented on, supposedly, Satoshi's last email sent to btc-dev mailing list
(1) The node incentives thing doesn't seem technically feasable. Or rather, the system had that built in but it was undermined by pooled mining. We now know how to avoid any _need_ to run pooled mining now, but it's always less costly to do so (due to the costs of running a node).
He was referring to this particular Satoshi's (?) statement "
I suspect we need a better incentive for users to run nodes instead of relying solely on altruism".
Maybe I'm too naive but I can't see why Justus' idea based on micropayment channels
(2) shouldn't be "technically feasible".
Secondly, even if we found a way to decrease the cost of running a node to 0, this wouldn't remove pooled mining.
The main two factor that are limiting solo mining are: operational node cost
and variance.
i.e. people join a pool to reduce variance rather than limit cost, especially if they represent a tiny fraction of the total hashing power.
(1)
http://lists.linuxfoundation.org/pipermail/bitcoin-dev/2015-August/010238.html(2)
https://bitcoinism.liberty.me/economic-fallacies-and-the-block-size-limit-part-2-price-discovery/