That's the very definition of "Need Before Greed!" You defer your own reward right now so someone else can have something nice, with the expectation that something nice for you will eventually come down the pipeline, until everyone in the party has a couple of nice things. Mild imbalances are ignored because the net benefit of having the item is usually higher, and if gross imbalances occur over a long period of time then you talk about balancing things.
When (not if) gross imbalances occur it's already way too late to talk about balancing things. The only way to prevent them is to - within bounds of practicality - not let them happen in the first place.
Also, even if a given player doesn't always play greedy characters, at some point that player might play one; and a greedy character with any intelligence at all could (and IME has) take a system like this and go nuts with it.
Granted, I think every group can play however the majority feels about it. If selling big ticket items is the expectation, and everyone joined the party with that understanding, then no harm is done.
Some times if an item is really useful to everyone is too big for one character to afford (e.g. a ring of regeneration or a rod of resurrection), a group of characters will buy shares in it just to keep it in the party. Or, if it's ironclad guaranteed that the same party is going to stick together for some time to come (rare, IME) then it'll just get carried forward to the next treasury as a party item.
A low-level party's treasury might look like (using our in-house item pricing and some conveniently rounded numbers):
Longsword +2 Lesser Vorpal - 23000 gp
Ring of Protection +1 - 3000 gp
Plate Mail +1 - 2000 gp
Scroll with some MU spells - 2500 gp
Horn of Fog - 3000 gp
Potion of Diminution - 500 gp
Potion of Levitation - 300 gp
Potion of Healing - 200 g.p.
various non-magical items (gems, jewelry, etc.) - 3000 gp
coins after expenses - 2500 gp
The sword is 23000 gp and the rest adds to 17000; total value 40000. Party has 5 characters, thus each one in theory gets an 8000 share. Each character needs to have about 3000 available for training. Keeping the sword means they have to sell off nearly everything else in order to afford to train, and means one character becomes much more powerful/useful than the others for the next adventure. If they sell the sword they can all train while keeping the rest of the good stuff in the party and sharing it around.
If they ignore magic item values completely they only have a treasury of 5500 gp, which won't get two of them trained never mind all five.
And if magic items are claimed and divided by a draft or choice procedure, there's nothing stopping the first chooser from taking the vorpal sword as theirs (whether the character can actuall use it or not) and then selling it. I've seen this done and believe me, in-character it ended very badly.