There were several reasons why a move to a top club didn't materialize for van der Sar (after leaving Juventus and in subsequent years)...
- A lot of them had quality goalkeepers of their own: Casillas at Madrid, Kahn at Bayern, Toldo at Internazionale, Cañizares at Valencia, and so forth. Others like Milan had decent options in Abbiati/Dida, and Ancelotti at the helm — who wasn't going to sign Van der Gol after what transpired between them in Turin.
- There was the underlying belief that he had been exposed as a ‟system player”, who had failed to grapple with the rigors of a different and more positionally reserved approach in Serie A — a major impediment as sweeper-keeper types weren't mainstream back then, and many clubs wouldn't have been willing to overhaul their approaches to get the best out of him.
- Edwin's initial transfer fee from Juventus was deemed prohibitive in certain quarters. Liverpool and Dortmund were interested, but did not want to fork out ~£8 million + big wages for a goalkeeper who had committed a litany of blunders in the recent past; and later on Fulham were not going to let him go without a proper recompense for the significant investment they had made in him (second most expensive signing in club history at the time).
- His confidence and concentration seemed shot in Turin, some of his performances in the disastrous World Cup qualifying campaign for the Netherlands weren't particularly reassuring either, and there were reports of issues with his eyesight as well — too many variables and uncertainties for a position that is associated with security and continuity.
Looking back, the most puzzling ones are United (perhaps Fergie was reluctant to make another move for him?), Arsenal (you would expect someone like Arsène to appreciate van der Sar's aesthetic and functional capabilities) and Barcelona (match made in heaven on paper, before the ascent of young Valdés of course), but all's well that ends well.
P.S. There's more to van der Sar's failing and subsequent ousting at Juventus than just his individual performances — principally, many were loathe to see a non-Italian between the sticks (a position associated with Combi, Zoff, Tacconi, Peruzzi, Anzolin in the eras gone by), and the signing of would-be Azzurri legend in Buffon was supposed to be a reinforcement of traditional values as well as a resounding show of ambition given the outstanding level of performance he had evidenced at Parma.