Lin is more along the lines of 8M so I'll exclude him from the discussion. The key thing to me is the ages. Paul and Williams are roughly Rondo's age and in Williams' case he has really fallen off (Paul has declined ever so slightly too). So I don't mind paying Rondo the same amount as Wall, Westbrook, Irving, etc. if he were approximately the same age. However, we'll be paying Rondo on past performance if we reward him with a 5 year deal at max, or near max, money. He simply won't fulfill that contract with his play especially during the later years of the deal. His athletically reliant game isn't one that ages well and unlike other PG's, who can compensate with any decreased athleticism with their shooting, Rondo can't.
I would love to see a chart on how athletically dependent players say 6-3 and under have performed during ages 29-34, which is more or less the age Rondo will be with a 5 year deal. Iverson, Marbury, Lever, KJ, Pack, Hardaway, Tiny, and Francis are a few that immediately come to mind. Trying to think of others.