I don't know why Disco died, but Video killed the radio star, or so I heard
I liked some of the songs from the disco era / genre, but like all genre's of music, I like the songs, not the artist or genre of music.
I will listen to Donna Summer, KC and the Sunshine band (but I HAVE
to turn off the BeeGee's when I hear their whiney, screechy, just got kicked in the nads voices) just as I will listen to Nora Jones, Sarah McLachlan, BB King, Elvis, Kenny Wayne Shepard, Cake, David Sanborn, Sass Jordan, Styx, Kid Rock, Frankie Valli, MegaDeath, Disturbed, Etta Jones, Bob Segar, Ziggy Marley, Prince, Klymaxx, Ella Fitzgerald, Louie Armstrong, The Temptations, Ted Nugent, Rick James, Warren Zevon........ and the list goes on and on...... like others have said, Disco ran it's course just like white guys wearing afros, bell bottoms, Member's Only jackets and Jordache jeans. And after a while, some (most) of the songs started sounding very much alike.
Road Captain, ELO wasn't "Disco"..... I think they were trying the same thing "The Who" and "Queen" did much more successfully, tried doing "Rock Opera" but in a different genre of music and not as well as the two mentioned above.