> but it is the most important property to understand: the rules are the rules and no one can change them without pretty extreme buy-in

At least in the case of the Bitcoin lineage, _tightening_ rules is not too hard (soft fork), while _loosening_ rules (eg. increasing supply via hard fork) is hard.

If you are the dev, control all miners and run all the nodes of your fork - everything becomes trivial (and quite useless)