I'm sorry, but this underpaid story line is hogwash. If anything, the military is doing a poor job of selling the actual monetary value of enlistment. Let's do a little math ( I do this for a living.)
E2 pay @ 2 = 2402/month
Average rent in the US = 1502 (lets be generous and say they have a roommate so $750/month
Average food expense for 1 person = 342
Tuition assistance max per year $4-4500k
By my math, that is $3869/ month or $46,428 per year.
Also, I don't know where you get that the TSP is a mediocre retirement plan. Yes, it's not a pension, but in terms of max contributions and low fees, it is at least on par if not better than almost any other 401(k) that I have seen.
Do you know many 20 year olds that have a comp package of $46k per year at Chick Fil A, or Popeyes or Wal Mart? I don't.
Let's also not forget GI Bill.
In my state, GI Bill tuition and fees + BAH + book stipend is equal to $39,180/year so a total economic value of $156,720 for 4 years (actually higher if you factor in BAH is not taxable.
So the economic value of a 4 year enlistment for someone who is motivated and maximizes the opportunity is somewhere in the neighborhood of $342,432. 4 years of service, potentially learning a valuable skill and also what equates to a full ride at the state university of your choice. I will wait to hear of any private sector opportunities that await the average 18-22 year old with a high school diploma that even comes close to this.