...based on experience of escaping from a master and the direction of my subsequent transformation, I can say that that the guru/disciple tradition is an antique one, and thoroughly optional.

Another conclusion you could have drawn from your experience is that "the guru/disciple tradition" was just not for you. To say it is "antique" is to superimpose your subjective experience on universal reality, which is something one must check, to be fair.

Your protective attitude to your master is a good example of the kind of self  limitation and waste of energy that devotion imposes on its practitioners.

That makes no sense. Would you feel the same way about a husband being protective of his wife? Limiting and a waste of energy?

Devotion is not something you practice but rather it is a relationship based on love. Nothing is "imposed" when love is at the root of it.

...I think a master will only make you exclusive and defensive. and probably arrogant.

You imply you are somehow above this? Look mate, we ALL want to feel we are apart from the masses, and actively look for ways to make ourselves feel that way. We ALL defend what we love and believe in. And if we are not arrogant we are are probably self-depricating. The differentiating factor is that some people care too much what they look like to others, while some don't care enough. Somewhere in between is where most of us lie.