Upon activation of The SegWit Omnibus Changeset, previously fully-validating nodes are rendered non-validating nodes, as they are incapable of validating SegWit transactions.
The only thing they don't validate is segwit signatures.
Thank you for confirming.
What if the number of bitcoin users increases by by some factor due to new entrants, and a few of them fire up nodes, such that absolute node count rises while percentage drops?
This is an effect that was reasonably expected in 2011/2012 which has been thoroughly debunked by experience.
While that may be true, past performance is not guarantee of future results. There are enough variables in this system that it is hard to interpret causality for future perturbations. But more to the point, I was trying to drive to forevernoob's personal definition of 'decentralization'. I feel the conversation is difficult, as many use 'but decentralization' as a war cry, but never reveal what the term means to them.
In Core we've been working frantically for years slamming out performance improvements to try to use optimization to compensate for load increases to protect decentralization.
Thank you for the effort. But now that you've invoked the buzzword, I am now interested in your personal definition. Hypothetically, would such a situation (increase in absolute number but decrease in percentage of users) represent -- to your mind -- centralization or decentralization? And is the set of non-mining, fully-validating nodes the most critical decentralization dimension of the system?