You want to fill the two hardest positions in football, goalkeeper and goalscorer. Plenty of teams try, very few manage. It just occured to me today that our situation post-Big Nev was very similar to Manchester United's post-Schmeichel. Both bought several promising keepers none of which lasted long (Gerrad, Simonsen and Wright were all highly thought of at the time).
And every team on the planet wants a goalscorer. But guaranteed ones are way out of our league.