I really don't think you can compare 80s goths with the modern plastic 'goths' at all, as they're completely different social groups with different ideas about...just about everything, really. TO me, plaggie goths are in a similar league to chavs, whereas if you don't wear the right uniform and listen to the right bands, you're "not goth" and a social outcast. I think these 2 definitions from Urban Dictionary (with a couple of my amendments) sum the difference up quite well.
Definiton of a Goth
1) A person who likes to dress and act differently to the other people in society, normally in black but some like much brighter colours. They tend to be thinkers, intelligent and more often than not highly creative. They have a satyrical sense of humour, and are able to laugh at both themselves and other people. They listen to and appreciate all sorts of good music. Like *all* social groups, they can be gay/depressed/weird/mentally disturbed, but more often than not they are just normal people.
2) An offshoot of the nu-metal clique who think that to *really* piss off their parents, they'll dress all in black and talk about death and suicide whilst listening to Cradle of Filth, Marilyn Manson and Slipknot because it's "cool". They will always totally disregard and ridicule any music that is not "goth" or any band that has fallen out of fashion that week. They tend to have very little idea of the other type of goths (or anything else other than themselves for that matter) and will probably change their fashion once it becomes "uncool" again.