Now I'm curious, so here are all the teams with the number of players that they drafted themselves on their roster.
23 - Arizona
19 - Atlanta
24 - Baltimore
20 - Buffalo
24 - Carolina
26 - Chicago
18 - Cincinnati
15 - Cleveland
26 - Dallas
17 - Denver
20 - Detroit
28 - Green Bay
17 - Houston
27 - Indianapolis
26 - Jacksonville
19 - Kansas City
12 - Miami
17 - Minnesota
20 - New England
15 - New Orleans
19 - New York Giants
17 - New York Jets
22 - Oakland
24 - Philadelphia
26 - Pittsburgh
23 - San Diego
27 - San Francisco
22 - Seattle
19 - St. Louis
22 - Tampa Bay
23 - Tennessee
17 - Washington
I see no correlation between the number of players that a team drafted on their roster, and how good that team is. Some of the highest numbers include both good teams (Colts, Steelers) and bad teams (49ers, Packers, Jaguars), and some of the lowest numbers also include both playoff teams (Dolphins, Vikings, Giants) and double-digit losers (Bengals, Browns.)
The thing is, just because a player is still on the team that drafted him, that doesn't mean he's not a 'bust.' Just look some of the players that Oakland drafted that are still on their roster: Robert Gallery, Michael Huff, Marques Tuiasosopo and Anrew Walter were all drafted in the first three rounds.
Bottom line is that just because the Patriots acquire a few more players through trades and free agency than the Steelers do, that doesn't mean the Pats are not as good at evaluating talent.