The constant of those teams is that they have a franchise QB whilst the teams picking at the top of the draft are pretty much always in need of a franchise guy.
You say that RM has found 'just Carr, Mack, Jackson, Cooper' as if any team could find those guys. Look at Jacksonville for instance in terms of their first round picks since 2011: Gabbert, Justin Blackmon, Joeckel, Bortles, Fowler and Ramsey.
In contrast, since RM took over as GM our first round picks have been DJ Hayden, Mack, Cooper and Joseph. No brainer on which group I'd rather have.
It's easy to draft players when you take hindsight into the equation. To get your franchise QB, the best defensive player in football last year and a true #1 receiver in the league who has set records which haven't been seen since Randy Moss. If it was so easy, every team would have big turnarounds from mediocrity to success within a very short time frame.
I actually think RM isn't going to have problems drafting later in the first round. He's found Carr, Edwards, Jackson, Carrie, Rivera, Murray etc in the lower rounds, and that's before we look at many solid undrafted free agents such as Jalen Richard.
This team isn't just built solely on a few nice picks at the top of the draft.