21 was huge at the time, but does anyone still spin it? Thriller, Beat It, and Billie Jean are all still club mainstays and get plenty of radio airplay. I haven't heard a song off 21 since like 2012.
I really think people are underestimating the influence Thriller has. Thriller wasn't just some top selling pop album. It was basically the Symphony No. 9 of modern times. MJ wrote the damn book that everyone is still copying to this day and will continue to copy till we are long gone.
I don't think there will ever be a single album or artist as universally appealing. The music industry has changed so much and there are so many niches and lanes for people to get their music from that I don't think we will ever see artists like MJ or Prince or the Beatles that dominate the culture like those guys did. In terms of impact Kanye might be the closest modern guy but even he isn't on that level.
Panda Bear - Person Pitch
Modest Mouse - The Moon and Antarctica
Boards of Canada - Geogaddi
Radiohead - OK Computer
Arcade Fire - Funeral
Animal Collective - Merriweather Post Pavilion
Burial - Kindred
Kendrick Lamar - To Pimp a Butterfly
The Field - From Here We Go Sublime
Clark - Body Riddle
DJ Shadow - Endtroducing...
The Avalanches - Since I Left You
The Books - The Lemon of Pink
and many other things i dont remember off the top of my head
I really wouldn't say that many Radiohead albums past OKC split their audience. There are disagreements about which ones are better, but you would be hard pressed to find people that dislike Kid A or In Rainbows. Their other albums, yes, but their trinity of OKC/Kid A/In Rainbows is the top 3 of most Radiohead lists 98% of the time.
At the time, Kid A and subsequently Amnesiac were incredibly divisive. Don't get me wrong, it gave them a whole legion of new fans who were never familiar with the My Iron Lung EP/Pablo Honey/The Bends-era Radiohead, but a huge number of those early fans detested the direction they went in from Kid A onwards. What was good for Radiohead was for every original fan they lost, they gained two new ones.