Maybe
i guess you can always think about ‘wishing you were at woodstock’ or some other seminal gig, but otherwise does it really matter when you ‘get’ a band? – at the time they made the music or 250 years later, if you started to like mozart – would you care that you weren’t born at the time?
Personally i was into similar rock/metal to you, and had a great time going to those gigs, wouldn’t have had time going to anything else anyway, so when i discover the Smiths or something now i’m not that bothered that i never saw them live.
music is only ‘cool’ in a small circle of folk. Most of the metal i listened to would not be cool by most people’s standards, but if i was first to get an album by some new band then i might have felt cool amongst my friends for a while – so what.