A minor correction: Tolkien himself
totally strikes the balance between "high art" and entertainment.
(Unlike the crowd of his epigons.)
If you want to avoid pure "high art" (gosh, how I hate this categorization
), I'd recommend some of the more sophisticated "genre" writers (G. R. R. Martin, Asimov, Holdstock, Gaiman - or the aforementioned Tolkien, but you seem to have read and misjudged him already
...). Or Moore's graphic novels...
I'm quite uninterested in contemporary mainstream, so I can't give recommendations or warnings in that area... But many of the big names from the 20th century canon (Remarque comes to mind) strike that balance you seem to look for quite perfectly.
Why last 100 years, by the way? :-) More good stuff was written BEFORE 1900...