I don't know where this magical mastery of the cap has come from but that is total conjecture at this point. They just spent 21M on a DE and are on the cusp of extending the QB for top 10 money and still have the RB, CB and LB to go.
I think the word "expendable" is a little strong since he is the juice to the offense but at 13-15M for a RB, he can be replaced and I see him as more of a luxury item instead of a necessity.
I do agree with the OP about how the Patriots would play this because if Michel continues to perform, he will not get a 2nd contract from Belichick. However, why single them out? There are no similarities between the way he runs that team and they run this one.
BTW, as long as we're comparing the Cowboys to the Patriots, no way Belichick does that Lawrence deal so start with that. He wouldn't even pay a healthy player almost at the same level less money than Lawrence got.
Before you start praising these people as having learned anything, you should wait for the movie to end because this one's just at the beginning.