Why is R5RS considered to be good

... when it includes ZERO functionality for a filter function or a fold function? Pathetic.

R6RS was a smart move. Too bad that ivory-tower academics felt it was too useful.

filter and fold shouldn't be in R5RS.

they can just be implementing as a simple recursive function in a portable way.

The better approach is: Language + standard libraries. R7RS sort of tries to do this but fails.