Much of that club's success at the time was down to the academy - as was shown when they were all sold.
It really wasn't. Here is the squad the year they finished 5th:
12 Shaka Hislop (Hammer of the Year) GK 37 0 2 0 2 0 July 1998 Saudi Sportswashing Machine
15 Rio Ferdinand CB 31 0 1 0 1 0 November 1995 Academy
19 Ian Pearce CB 33 0 1 0 2 0 September 1997 Blackburn Rovers
6 Neil Ruddock CB 27 0 2 0 1 0 July 1998 Liverpool
8 Trevor Sinclair RM 36 7 2 2 January 1998 Queens Park Rangers
11 Steve Lomas (captain) CM 30 2 March 1997 Emirates Marketing Project
18 Frank Lampard CM 38 5 1 1 2 July 1995 Academy
7 Marc Keller LM 17+4 5 0 0 1 0 July 1998 Karlsruher
29 Eyal Berkovic AM 28+2 3 1+1 1 June 1997 Southampton F.C.
10 John Hartson CF 16+1 4 2 1 February 1997 Arsenal
14 Ian Wright CF 20+2 9 1 2 August 1998 Arsenal
Important players
10 Paolo Di Canio CF 12+1 4 January 1999 Sheffield Wednesday
20 Scott Minto LWB 14+1 January 1999 Benfica
9 Paul Kitson CF 13+4 3 February 1997 Saudi Sportswashing Machine
13 Marc-Vivien Foé CM 13 January 1999 Lens
4 Steve Potts CB 11+8 1 2 May 1984 Academy
17 Stan Lazaridis LWB 11+4 2 1 September 1995 West Adelaide
3 Julian dingdongs D 9 2 1 1 October 1994 Liverpool
16 John Moncur CM 6+8 1 June 1994 Swindon Town
So apart from Ferdinand/Lampard, nearly all the rest signed by him.