Usually when I look through a list of musicians, I find myself asking "Who? Who? Who?" In this case, I frequently said "Yes! Yes! Yes!" (even for the Honourable Mentions). A few artists I knew by reputation, and a few I didn't know about at all, but you have made a compelling case for 1998 as a golden year.

I checked to see if any of my faves had an album that year. The newer of my musicians hadn't yet released anything, and many of the older folks had ceased to record, or didn't produce anything significant in 1998 (e.g. Scott Walker straddles 1998 with "Tilt" and "The Drift"). But a few artists from the 60's-70's contributed to that golden year:

Robert Wyatt Dondestan Revisited (technically not just a re-release)

Ray Davies The Storyteller

Billy Joe Shaver Victory

Still (imo) these are not as important as most of the artists / works you list here.

It may turn out that 1998 was a kind of pivot year--capitalizing on the best of the past while anticipating the great music that would follow.