The line I've highlighted was true in the Championship but it's not true now we've got money, although that may be because players in their mid-late 20s at our level will be on wages out of our reach.
A while back I looked at the profile of players we signed since Wilder joined. Basically speaking:
Summer 2016: avg age 27 - mainly experienced pros (Clarke, Duffy, Wright), plus potential (Fleck, Moore, O'Connell). 7/9 aged 25 or over.
Jan 2017: avg age 26 - get over the line (Hanson), potential (Carruthers) 1/2 aged 25 or over
Summer 2017: avg age 26.5 - freshen up the squad (Lundstram, Baldock) plus Championship experience (Stearman, Donaldson). 4/8 aged 25 or over
Jan 2018: avg age 26 potential (Evans, Leonard) plus random (Holmes). 2/3 aged 25 or over
Summer 2018: avg age 27 - quality experience (Egan, Norwood, McGoldrick). 5/6 aged 25 or over
Jan 2019: no permanent signings
Summer 2019: avg age 26 (24 excl. Jagielka) - high potential (Mousset, McBurnie, Robinson). 4/8 aged 25 or over
Jan 2020: avg age 25 - potential/squad depth (Berge, J Robinson, Rodwell). 2/3 aged 25 or over
Updating this season's entry:
19/20 - average age 25.7 (skewed by Jagielka - without whom it's 24.4; first team players 22.3)
Synopsis - building for the future
Summer average age 26 (24.4 exc Jagielka):
McBurnie 23, Mousset 23, Verrips 23, C Robinson 24, Osborn 25, Morrison 26, Freeman 27, Jagielka 37
January (average age 25):
Berge 21, J Robinson 26, Rodwell 28