Re: Not putting everything into loans to get the 7.6% return vs. (i) investing in other things or (ii) putting money into 401k:
(i) I cannot fathom any investment that has a high enough IRR to justify not taking the 100%-certain 7.6% (and this number should be higher - the smart money puts all of their loans into 25-year repayment but still pays the same amount overall. This allows you to put more money into the highest-rate loans. Consolidating makes absolutely no sense when you have some loans at 6.8 and some at 7.9/8.5 (depending on when you took your GradPLUS loans out)). Sure, you might be able to get 10% elsewhere - or you might get stung. 7.6% is a really, really high risk-free rate; getting another 2% doesn't justify the additional risk you take on.
Additionally, the 7.6% isn't subject to another level of tax (presumably capital gains, because getting higher than 7.6% on interest probably isn't going to happen) - which makes the 7.6% even more attractive.
(ii) I'm not going to contribute to my 401k. If your firm has a match, then you obviously contribute up to the match - that's a no-brainer. But if the firm doesn't have a match, I am not confident enough that any 401k gains are going to outdo the certain return on paying loans - not to mention the flexibility that comes with paying down loans faster (unlike other investments, you can't raid the 401k to pay off your loans early, if you have a change of heart). More importantly, I would say that the chances of taxes being much higher when we're old enough to draw on 401ks makes the tax deferral aspect be of questionable value. Again, you're considering an uncertain return later vs a very certain return now.
There is a big liquidity advantage to having $75k in the bank versus having paid it off in loans.
A reasonable person doesn't leave $75k sitting in a bank (unless you're filthy rich and need that much money at a moment's notice because you're blowing something like $75k /month). Short-term investments, on the other hand, are risky, especially when you're talking about 2-3 year investments, like we are here (i.e. the cost of 2-3 year of interest in repaying student loans vs. the potential gain of investing the money for those 2-3 years). Personally, I would rather be debt-free than take risks with hopes of making an extra 2% interest (relative to gains if the money went towards repaying the loans) on that $75k. It'd be a different story if the economy was booming right now, and people were seeing something like 20% returns on large cap stocks.
Just to be clear, I'm not saying it's reasonable to not save anything. But $75k is a lot of money to just sit on when the economy is shitty like it is right now (especially if you live somewhere cheap like Texas), where you can't very easily make returns exceeding your student loan interest rates.
It's not about making a return on that money. It's about having short-term assets that you can liquidate relatively quickly just in case. What if you're presented with an unexpected opportunity? It could be a business opportunity or even just finding a great deal on a house.
Say you owe $200k. Your payments are $2,400 per month. You put an extra $1,100 per month into your loans, for a total of $3,500. Now, say your take-home is roughly $8,500 (you live in NJ). Allowing for $2,500 rent and $1,000 other expenses, you've got $1,500 left over each month. What to do with it?
If you don't put it towards loans, your total loan interest over the life of the loan will be $50,000. If you do put it towards your loans, you'll save $20,00 in interest. But, in the first scenario, even with a weak rate of return of 5%, you'll have earned $17,500 in interest, $15,000 after capital gains. So you're only down $5,000. What is the value to you of being able to take advantage of an opportunity by having a relatively large liquid savings?