Falling asleep
How are the charts a "reflection of depth of a genre" and what relationship does depth (what ever that means) have to quality exactly?
Up to 2001 in your list, how many were what I'd call guitar indie music before the strokes? That was the original point.
1998
Mercury Rev - Deserter's Songs
Beta Band - Three EPs
Tortoise - TNT
Boards of Canada - Music Has The Right to Children
Belle and Sebastian - The Boy With The Arab Strap
1999
Sigur Ros - Agætis Byrjun
Flaming Lips - Soft Bulletin
Bonnie Prince Billy - I See A Darkness
Wilco - Summerteeth
Pavement - Terror Twilight
2000
Doves - Lost Souls
Radiohead - Kid A
Lambchop - Nixon
Primal Scream - Xterminator
Pj Harvey - Stories From The Land Stories from The Sea
Most of those albums aren't guitar rock/indie bands, since the strokes who brought that style back, there has been a deluge of that kind of music, when by common consent there wasn't much of it between 1998 (the end of Britpop) and 2001.