Of course it is fair.
I think a lot of it has to do with the draft. The draft is not a crapshoot - Price went #2, Kershaw went #7, Grienke went #6, Strasburg went #1, Beckett went #2. Hell, Andrew Miller went #2. Premium arms don't show up often and get gobbled up.
The Red Sox have clearly tended towards lower risk strategies with earlier picks - position players up the middle (in other words, high caliber athletes) and college arms (who have a solid amount of probability). Prep arms are historically very risky, but alas it is also where you are going to find the star material. I think the risk aversion in the draft is fair game. Now it has allowed the Red Sox to have a remarkable stockpile of middle of the field talent - which is nearly as hard to amass as pitching.
Cubs operated more or less the same way - their stockpile is in position talent ... I think just because of the shortage of arms. Their big coup was straightening out Jake Arrieta, along with landing a quality #2 like Lester clearly.
What the Red Sox have done wrong with pitching imo has been not to be as aggressive converting starters at the farm level (which is really the best way to find bullpen talent). It was clear as day that Webster was really a potential bullpen weapon but too much time was spent thinking he could be a quality starter. Ranaudo and Barnes as starters are a little different - less wipeout stuff. Barnes will be a perfect fine starter for somebody - not amazing, but a capable workhorse sort. The development has been ok, but I do think there is question on the ceiling they have gotten in on that.