@Numquam
Of course the 50 move rule is rarely used. If that means you're not interested in the subject then why talk about it?
If you go to a chess club and there is an argument over the rules in a friendly game I think the argument would be resolved by consulting the FIDE handbook. The chess club won't give you a set of rules specific to the chess club in advance. I think that would be understood in friendly games in other environments.
You say that FIDE doesn't decide the basic rules of chess, but on my reading of Chapter 1 art. 1.4 of the handbook FIDE thinks it does. I think so do most other people.
I agree that you need some rule in case of no progress. I regret its disappearance from the basic rules. You say it's the most used rule, but as of now I don't think the majority of games should be using it. No doubt they are, because there was precious little publicity about the change. I never saw anything in the daily papers about it.
But in any case the problem with the 50 move rule is it's a century out of date. It's no longer adequate for players theoretical knowledge. That can only be more true as time goes on because players can now practice endgames that have received little analysis in the past against EGTBs.
MARattigan: 'Fide chess tournaments' are all tournaments which are officially registered for rating purposes. As for the rest of your argument, they've just separated Basic Rules and Competitions Rules because there was considerable overlap between them. Over the course of many years (coinciding with the introduction of increment play and online forums discussing the rules) the rules were updated virtually every two years or even more frequently, and this lead to inconsistences and redundancies.
OK, but I don't follow how having two sets of rules would lead to fewer inconsistencies than a single set.
Are you saying FIDE rules should be ignored in friendly games, at the chess club say, and if so would the 50 move rule be in force or not? FIDE should publicise the fact, because there is a widespread feeling among the general public, in Europe at least, that FIDE is the ultimate authority governing these.
The problems discussed earlier regarding the 50 move rule of course apply whether it's in force or not, regardless of who is accepted as the authority.
The FIDE rules are completely irrelevant in chess games outside of FIDE tournaments and it doesn't matter what rules FIDE considers 'basic' rules. What matters is what the chess players think or the chess club thinks. The basic rules of chess are not decided by FIDE. I am pretty sure that the large majority includes the 50 move rule in the basic rules unless they don't care to cover all cases within the rules. You need some rule in case no progress is made and the 50 move rule is the most used rule. In friendly games players may not bother to count the moves though, but most people aren't that stubborn when the position is clearly a draw. People either use rules to cover all cases or they decide what should happen when such a situation occurs on the board. The 50 move rule is rarely used anyway.