Well, K+A vs K is a generally won end-game, and piece values have no meaning there. A win is a win, whether you achieve it with Archbishop, Rook, or Queen. That doesn't mean A=R=Q in a context with many pieces. Any piece can be the difference between a win and a draw in a late end-game. E.g. King + Ferz + Bishop on opposit shade is a win vs bare King, and losing the Ferz is just as bad as losing the Queen in K+Q vs K, as both lead to a draw.
Well, K+A vs K is a generally won end-game, and piece values have no meaning there. A win is a win, whether you achieve it with Archbishop, Rook, or Queen. That doesn't mean A=R=Q in a context with many pieces. Any piece can be the difference between a win and a draw in a late end-game. E.g. King + Ferz + Bishop on opposit shade is a win vs bare King, and losing the Ferz is just as bad as losing the Queen in K+Q vs K, as both lead to a draw.