There's an important difference here between canned food and pretty much everything else. Expiry dates tend to be early for perishable goods, but IMO this is an

There's an important difference here between canned food and pretty much everything else. Expiry dates tend to be early for perishable goods, but IMO this is analogous to buildings being overengineered. Canned goods, on the other hand, should last indefinitely so long as the can itself doesn't fail. There's just not a whole lot of relevant chemistry going on in a sterile, low oxygen environment. I suppose permeability of the can itself to oxygen (depending on what method was used to seal it) could become relevant on a long enough timescale, but if the contents are truly sterile even that shouldn't make much difference. If anything does happen to the contents of the can, as noted in another comment there will almost certainly be a visible change in volume (ie the can will deform).