Couldn’t Glenvar pawn the infinity wing box off to the world atheneum, maybe have them crack the code to magically generating infinite food? As a side note can magic even create food? And is their spells that can create infinite food already available?
Sure he could! The thing is though, there are countless enchanted items all over Looming Gaia that do all kinds of wacky shit not unlike the unlimited wing box. Typically these enchanted items are forged by master mages and they have some kind of stipulation attached to them; like a limited number of uses, or they can only be used by a certain person, that sort of thing. The Edge of Second Chances is one of those objects, for example. They are everywhere, so unless they have a particularly unique power or origin (like the Divine Executioner) then the World Athenaeum probably wouldn't be interested.
Similar to the infinite wing box, every maenad manifests with an "everlasting amphora". These have been featured in multiple stories, but basically it's a magical amphora with an infinite supply of wine, but it'll only pour out under these conditions:
A) The maenad's hands are touching the amphora.
B) The maenad wants it to.
So if you think you're just going to steal a maenad's magic amphora and have yourself an infinite supply of booze, think again. Also, magic never just materializes something from nothing. It has to take energy from some other source--and that source can be literally anything, including objects and people. Usually it takes energy from whichever mage casted the spell. Or a crystal battery, which are charged by mages using their own energy, so in a roundabout way it's still taking energy from mages even when it's drawing from a battery.
So, by this logic, a mage could forge an object that creates infinite food. But this objects would have to steal energy from some other source and convert it into food, it couldn't just make the food from thin air. Maybe it would convert tree bark into meat, or sap energy from a battery to create grain.
The point is, you'd have to make some kind of sacrifice to the almighty infinite wing box to get your wings.
On top of that, magic has a mind of its own and it really doesn't like being exploited by people, especially if that exploitation creates unbalance on Gaia. This is why spells sometimes backfire or don't work for what seems like no apparent reason.