Not sure the scope of this as believe that 99% of music is rubbish and there's too much music and not many years left to filter through finding the worthy stuff.
If i was to keep it to artists who are the darlings of music journalists (i.e. they have a lot of respect in the biz) then would have to say that the following deliver less than 1% greatness in my world...
Van Morrison (can't think of a single track tbh)
The Blue Nile
99% Prog Rock. Horrible genre of music.
Artists who have too much credibility and, in my opinion, produce(d) about 50% or less greatness output (....like many artists i suppose)...
Love (apart from forever changes and a bit of da capo .....what else?)
The Fall (up and down like a yo yo)
Artists who got loads of cred and muso journo points and hit the mark on most occasions....i.e. the greats to name a few....