This worry about cost of nodes is the ultimate FUD, imo. (Not saying that you're FUDding, but you can find a lot of it.) The number of people who could just barely scrape together the cost of the minimal possible hardware to run of node are a negligible portion of nodes overall. The cost of hardware has been falling faster than the blockchain's been growing.

That's not the same thing as recognizing that some people are going to need to upgrade, and won't bother doing it. That kind of "I don't really care enough to keep fucking around with this" will assuredly result in attrition. But a bunch of those lost will be replaced by new people, and non-economic nodes have a tenuous value to the network anyway.