Let's do some simple math...AGAIN:
7 draft rounds x Average NFL career 3.3 years = 23 players (in a perfect world).
NFL roster 53 + Practice Squad 12 = 65
Under perfect conditions, 65% of your roster needs to come from other than the draft.
Reality is more like 75% or more of your roster must come from other means.
Mathematically you CANNOT use the draft to build a complete roster.
This is what Belichick does so well. Build a roster despite poor draft position (or poor draft results).
Do the Pats need to improve their drafting? Absolutely.
Sometimes I think BB has distain for the draft because he knows people over value it (he calls it freebies).