Rule #1 is... a very bad rule. Rather, the mid player should have priority.
ye. courier should only be used by mid player if he is about to bottle crow. Better?
If he's not, carries can use it as well if theres no demand for the mid guy.
There is a good reason why mid players need the courier and ppl on other lanes do not as much. There are the side shops on off and save lane, and mid theres nothing so the other guys can at least buy "some" items on their lanes. Of course not everything, but most mid players do not care about it.
Stop feeding, kuoin and learn to play! A support shouldnt die either that much. Of course he dies more than a carry usually. I for example die for my carry, e.g. as Venge I swap with him so they often kill me instead of him. Or bodyblocking the enemy so the carry can run.
They may cry about it in games with ppl having 100+ wins but in high bracket ppl usually know the roles and understand stuff.