Some of the increase could be offset by taking half of that 1.4B and giving it to service members directly.
The government still saves money, and the service member has much of the increase offset. All the money spent on salaries and other nonsense is cut out. So of the money being spent, more of it would go to the actual service member.
I'd say the only people that would see a significant change in the finances would be retirees. Assuming they wouldn't be given a raise, they'd be paying the full increase in grocery costs.
The problem with this idea is again the math. According to the FY2012 DeCA financial report, the return on investment is about 2x for the money spent on this benefit, meaning that the $1.4B spent on DeCA by the government produces $2.8B in savings for shoppers there. So, to enact your plan, you would have to cover $2.8B, not simply $1.4B to have there be a net zero affect on the service member. Now the report does not break down the demographic of the shoppers... so if you drop everyone except active duty members, you might be able to reduce the overall savings number and thus save the $1.4B, but I think that is a tall order.
In addition, this is a benefit. Pure and simple. So by closing the commissaries you are reducing service member benefits. The options as I see it are:
1. Do nothing. Continue to provide service members a $2.8B benefit for the cost of $1.4B
2. Close the commissaries. Eliminate the $2.8B benefit and tell the service member to "suck it up"
3. Restructure the system. Spend a large amount of money on how to close the commissary, but increase BAS, or change pay scales, or figure out how to offset the increased cost on families through some other medium. If you trust the government to figure that out, then good on you. I doubt it would produce a 2 for 1 ROI. And once again, it would cost service members more. BUT, it would look great for a FITREP bullet because you saved the govt $1.4B!!! Even if you asked that bill to be paid by the military member.
4. Look at ways to reduce costs and work more efficiently within the current system. Maybe increase the surcharge (5%), which hasn't been changed in almost 30 years. Explore better logistics operations. Figure out how to minimize waste. Reduce SKUs to only the best selling items. Etc. Run a more efficient business in other words.
DeCA will always be a subsidized benefit of the military. It will never be self sufficient if it is still in place to be a benefit.
The bottom line is should the military service member bear the burden of increased costs in order to save the government money? My answer in this case is still no.