Probably one of the reasons that Tony is happy with GP - a decent keeper these days is north of £15m - Villa paid £20m for Martinez (who had previously only played 15 times in the EPL). I know we are transfixed by the short-term troubles, but longer term (as oft repeated) Potter is doing a great job in blooding the youngsters.
Plus there's no point spending £20m on a keeper while:-
DBD gets turned inside the opposition half.
DBD is now slightly behind and one on one with Saka
Webster & Dunk are completely mesmerised by the ball.
Gross & Bissouma allow The Cassette to gain yardage on them.
Spending £200m on ALL the keepers still isn't keeping out the goals this team is capable of conceding.