Hacker,
I think this letter is different from past letters in that it is more of a direct assault on General Schwartz, the others were on the culture of the force, this is directly in the face of the boss. Each one of those letters came a very interesting point in our history and the dynamics were slightly different each time. It is interesting that the letter took such a shot at Schwartz just as he is about to exit stage right. It is also interesting that the author picked SMJ to publish his/her concerns, I still haven't figured that out.
Personally I think we are at a major inflection point. The declining budget puts us as serious risk of becoming a hollow force again (sequestration will assure that), we are worn out from 10 years of constant combat, AND the economy is bad. You are exactly correct that we have not yet seen the mass exodus that was promised, but the economy has certainly kept that somewhat in check, as did the age 65 retirement and the increased UPT commitment. I am not a rocket surgeon but if the economy does improve I think you will see a major run for the door. My friends in big business share all sorts of stories about the major corporations holding back on investment and hiring, but if they get a sign things are truly on the mend there will be a lot of higher quality jobs available for military officers. Now to get in the weeds but there is well over $3Trillion sitting on the sidelines just waiting to jump into the market and I think it could be the tipping point. We are so far behind in AVIATOR production, it will literally take a decade to catch up unless stop loss or other drastic measures are used.
Welsh himself could hold the key, it will be interesting to see how he plays his cards. He is the one leader who through force of passion and leadership might sway the tide, but will he come out swinging or wait for the tide to go out. Regardless, I think we are in for a very rough ride the next few years and the increased frequency of the Dear Boss letters highlights the concern growing in the force.