I think the spice boys tag and the neil ruddock pile on is a little over the top. Surely they were somewhat to blame, but the core issue is the recruitment. What Ged brought was top class players into the team; hyypia and hamann in particular, despite all the discipline that he instilled results fell away as the recruitment got worse from 2002 onwards.
The spice boys tag is largely people forcing the evidence to fit their conclusions. Fergie says "the minute I saw them in white suits I knew we would beat them" and fans lap that nonsense up. It similiar to the body language experts that will be out in force in salah goes a few games without scoring
Insofar as the white suits are concerned I do agree. It's classic
post-hoc ergo propter hoc reasoning. If we had won that game another narrative would have been offered in its place: maybe something about the suits demonstrating our fuck-you attitude and determination and confidence. Talking heads for the next thirty years would have pontificated how without wearing those suits we could never have won. It's the suits wot won it. Etc.
Personally I have no issue with the suits. I mean they looked like twats but then footballers often do.
However, separate to the suits there was a different, more insidious problem about attitude and professionalism and concentration that the team at that time was exhibiting, and I guess 'spice boys' is as good a short hand term for that as any other
The rest of your points about recruitment are spot on