Unfortunately, there is yet no perfect food preservation method, YouTube videos about the ever-fresh McDonald's meal notwithstanding.

Using gasses like nitrogen or carbon dioxide will kill off bacteria, insects, rodents, etc., but they still can't totally prevent the degradation of raw food. I've never tried it, but I would expect that fresh food kept in nitrogen may not get moldy or spoil in the usual sense, but it would still decompose over time. Eventually, the nutritional value will decrease to the point that it may not be worth keeping and/or the taste will become inedible. Same thing with canned foods, MRE's, etc. You may not get sick eating really old canned foods, but you may gag on the taste or the texture.

Or think of aged beef. The methods used now allow the meat to age with very little, if any, bacterial growth, so the meat really doesn't "spoil" at all but it does break down and get soft (a desirable thing, in this case). If you just kept aging the beef, I assume you'd get some sort of gooey mess in the end.

No one is worried about the taste of mummies, and they are already preserved, so the nitrogen is really more of a secondary preservation strategy, not the main one. Anyway, just my 2 cents.