Not even major hashrate is needed for successful hardfork - what new nodes must do is ignore any node which does not comply to the new ruleset, it is as easy as that. Even
some coins laughed at by most people did it right (see Flappycoin, if node is not at least v3.1 it will end up ignored immidiately, you will never ever see it connect even for a split
second) but instead of just using what worked - which is what they did in the first place by cloning Bitcoin - so called developers opted for some untested techniques and stuff
that realy make no sense.