I got bored today and decided to take a look at all the first rounds since 1990.
I found something interesting. Less than 25% of the 1st round picks during during that 17 year period actually panned out to be substantial contributors in the NFL. I'm not talking about, Pro-bowl level or Hall of famer level performers here. Just starters or even contributing a decent amount of playing time as a reserve, which should be less than expected from a 1st rounder.
Take a look at the 90-93 1st rounders. You'd puke.
I thought about this some more, and I think you made this whole thing up. Less than 25% means that 7 or fewere first round picks start "or even contributing a decent amount of playing time as a reserve" (your definition). This is silly, but I am as bored as you, so I looked at first rounders too.
http://www.drafthistory.com/rounds/round_1.html
I looked at the 90-93 1st rounders, the rounds you say are the worst, and a quick glance shows me that almost all started, never mind merely contribute a decent amount of time as a reserve. I don't know how to format it but here is the list (there were 111 players drafted those three years, including supplemental. 25% is only 27. Want to look again before saying there were only 27 starters on this list
Drew Bledsoe - - Patriots - - QB - - 1993
Rick Mirer - - Seahawks - - QB - - 1993
Garrison Hearst - - Cardinals - - RB - - 1993
Marvin Jones - - Jets - - LB - - 1993
John Copeland - - Bengals - - DE - - 1993
Eric Curry - - Buccaneers - - DE - - 1993
Curtis Conway - - Bears - - WR - - 1993
Willie Roaf - - Saints - - T - - 1993
Lincoln Kennedy - - Falcons - - T - - 1993
Jerome Bettis - - Rams - - RB - - 1993
Dan Williams - - Broncos - - DE - - 1993
Patrick Bates - - Raiders - - DB - - 1993
Brad Hopkins - - Oilers - - T - - 1993
Steve Everitt - - Browns - - C - - 1993
Wayne Simmons - - Packers - - LB - - 1993
Sean Dawkins - - Colts - - WR - - 1993
Tom Carter - - Redskins - - DB - - 1993
Ernest Dye - - Cardinals - - T - - 1993
Lester Holmes - - Eagles - - G - - 1993
Irv Smith - - Saints - - TE - - 1993
Robert Smith - - Vikings - - RB - - 1993
Darrien Gordon - - Chargers - - DB - - 1993
Deon Figures - - Steelers - - DB - - 1993
Leonard Renfro - - Eagles - - DT - - 1993
O.J. McDuffie - - Dolphins - - WR - - 1993
Dana Stubblefield - - 49ers - - DT - - 1993
Todd Kelly - - 49ers - - DE - - 1993
Thomas Smith - - Bills - - DB - - 1993
George Teague - - Packers - - DB - - 1993
Dave Brown - - Giants - - QB - - 1992s
Steve Emtman - - Colts - - DT - - 1992
Quentin Coryatt - - Colts - - LB - - 1992
Sean Gilbert - - Rams - - DT - - 1992
Desmond Howard - - Redskins - - WR - - 1992
Terrell Buckley - - Packers - - DB - - 1992
David Klingler - - Bengals - - QB - - 1992
Troy Vincent - - Dolphins - - DB - - 1992
Bob Whitfield - - Falcons - - T - - 1992
Tommy Vardell - - Browns - - RB - - 1992
Ray Roberts - - Seahawks - - T - - 1992
Leon Searcy - - Steelers - - T - - 1992
Marco Coleman - - Dolphins - - DE - - 1992
Eugene Chung - - Patriots - - T - - 1992
Derek Brown - - Giants - - TE - - 1992
Johnny Mitchell - - Jets - - TE - - 1992
Chester McGlockton - - Raiders - - DT - - 1992
Kevin Smith - - Cowboys - - DB - - 1992
Dana Hall - - 49ers - - DB - - 1992
Troy Smith - - Falcons - - RB - - 1992
Dale Carter - - Chiefs - - DB - - 1992
Vaughn Dunbar - - Saints - - RB - - 1992
Alonzo Spellman - - Bears - - DE - - 1992
Chris Mims - - Chargers - - DE - - 1992
Robert Jones - - Cowboys - - LB - - 1992
Tommy Maddox - - Broncos - - QB - - 1992
Robert Porcher - - Lions - - DE - - 1992
John Fina - - Bills - - T - - 1992
Darryl Williams - - Bengals - - DB - - 1992
Russell Maryland - - Cowboys - - DT - - 1991
Eric Turner - - Browns - - DB - - 1991
Bruce Pickens - - Falcons - - DB - - 1991
Mike Croel - - Broncos - - LB - - 1991
Todd Lyght - - Rams - - DB - - 1991
Eric Swann - - Cardinals - - DE - - 1991
Charles McRae - - Buccaneers - - T - - 1991
Antone Davis - - Eagles - - T - - 1991
Stanley Richard - - Chargers - - DB - - 1991
Herman Moore - - Lions - - WR - - 1991
Pat Harlow - - Patriots - - T - - 1991
Alvin Harper - - Cowboys - - WR - - 1991
Mike Pritchard - - Falcons - - WR - - 1991
Leonard Russell - - Patriots - - RB - - 1991
Huey Richardson - - Steelers - - LB - - 1991
Dan McGwire - - Seahawks - - QB - - 1991
Bobby Wilson - - Redskins - - DT - - 1991
Alfred Williams - - Bengals - - LB - - 1991
Vinnie Clark - - Packers - - DB - - 1991
Kelvin Pritchett - - Cowboys - - DT - - 1991
Harvey Williams - - Chiefs - - RB - - 1991
Stan Thomas - - Bears - - T - - 1991
Randal Hill - - Dolphins - - WR - - 1991
Todd Marinovich - - Raiders - - QB - - 1991
Ted Washington - - 49ers - - DT - - 1991
Henry Jones - - Bills - - DB - - 1991
Jarrod Bunch - - Giants - - RB - - 1991
Rob Moore - - Jets - - WR - - 1990s
Jeff George - - Colts - - QB - - 1990
Blair Thomas - - Jets - - RB - - 1990
Cortez Kennedy - - Seahawks - - DT - - 1990
Keith McCants - - Buccaneers - - LB - - 1990
Junior Seau - - Chargers - - LB - - 1990
Mark Carrier - - Bears - - DB - - 1990
Andre Ware - - Lions - - QB - - 1990
Chris Singleton - - Patriots - - LB - - 1990
Richmond Webb - - Dolphins - - T - - 1990
Ray Agnew - - Patriots - - DE - - 1990
Anthony Smith - - Raiders - - DE - - 1990
James Francis - - Bengals - - LB - - 1990
Percy Snow - - Chiefs - - LB - - 1990
Renaldo Turnbull - - Saints - - DE - - 1990
Lamar Lathon - - Oilers - - LB - - 1990
James Williams - - Bills - - DB - - 1990
Emmitt Smith - - Cowboys - - RB - - 1990
Tony Bennett - - Packers - - LB - - 1990
Darrell Thompson - - Packers - - RB - - 1990
Steve Broussard - - Falcons - - RB - - 1990
Eric Green - - Steelers - - TE - - 1990
Ben Smith - - Eagles - - DB - - 1990
Bern Brostek - - Rams - - C - - 1990
Rodney Hampton - - Giants - - RB - - 1990
Dexter Carter - - 49ers - - RB - - 1990