That's obviously because you don't know any better. Numerous harmony parts are missing --- go back & listen to the original recording & compare them, and next time, know what you're talking about before you post it.
What blows me away is that these guys met while working at a bar where Dave was the bartender. Yiu could spend years searching and not find a better group of musicians and these dudes just met on accident?
All these really good musicians in this band and nobody can sing harmony strong enough to cover all the parts on the record. It seems that by the 90's, the ability to sing harmony was out the window wiht the exception of a few talented souls. This is just a observation of the state of musicianship in general & prevalent most everywhere, not a denigration of this band's music or talent to play --- just the lack of live vocal talent here & most everywhere by the mid 90's.