Sure they system will never truly run dry, but supply can be brought down so low as to effectively kill it for other players (after all, the less the supply the higher the price for what little is left).
And really there is no way to predict what the ramifications would be - but you can bet the first job of a large number of people would be to try and break it in their advantage. Anything I'd be saying would just be imagination and spitballing unless we saw it in practice, but I could imagine, say, a group taking all the valuable commodities from station A, and taking it to their guild's various other bases, and blockading station A from non-guild members. Warn them they'll be shot down if they try to dock there (not that it would matter because they'd have very low supply anyway) and if they want to buy valuable commodities, they're more than welcome to go to their player bases to buy it (in which case they get even more money).
Maybe it wouldn't work that way, but there is the matter of the genie and the bottle. If you introduce a mechanic and then realize that it's being exploited all to hell to the detriment of the game, it not only takes a long time to fix, but causes a huge uproar when any attempt to fix it is made.