Some people are better with observation than theory, and need to think through problems by way of examples.

So consider a case where there are 100 million full nodes, and only 100 of them support all economic activity in the world. All others only validate and relay valid blocks.

To function, the 100 do not require the others. They require only to obtain blocks, which of course arise only from each other. They connect and relay with the others, but get no actual information from them.

At some point the others all decide to hard fork, resulting in their nodes rejecting the 100’s blocks. The 100 continue to operate unaffected.

Or at some point the 100 decide to hard fork, resulting in the others rejecting their blocks. The 100 continues to operate unaffected.

Now consider the case in which economic activity, measured as the value of coin being accepted in trade on average over time, is evenly distributed among the 100. And in the case where the 100 hard forks, 1 of them (representing 1% of their economy) decides to not adopt the fork. This one remains with the others, the 99% continue. Also consider a scenario where 99% reject the fork, and 1 forks himself off.

In these cases, the 1 has 1% of the economic power, to either compel a fork, or resist one, and the 99 have 99%. This is not hash power, this is economic power. There is no implied majority control outcome, but there is outcome driven by power.

And now consider the 999,999,900 other nodes. They have zero impact on either scenario. They are totally irrelevant. The 100 doesn’t benefit from them in any way. In fact, they end up representing a Sybil against the economy.