This is all dependent on the campaign and the players.
First, the half sell price limitation can easily be avoided. I do not know of any games where every 11th level PC has exactly 66K and every 12th level PC has exactly 88K, etc. PCs have a variety of items, some bought, some made, some found. Since this varies greatly from campaign to campaign, it should also vary from PC to PC.
In fact, a DM forcing all PCs to have nearly the exact same wealth would result in a pretty skewed situation. This can only be enforced by a combination of the DM and the players. Recently, I added up the wealth of the PCs in our group and one PC had more than twice what anyone else had. The players in my group do not know it and most of them did not care: although we did start a new system for those who did care of the DM keeping track of wealth in certain categories and the PC who is lowest on the totem pole gets to pick first for newly found items. But before this change, their idea was to give items to whomever could use them the most effectively. Other players (or PCs) in a different game might be very detailed and party wealth balanced oriented.
As to the original question, really, who cares? If an 11th level PC wants a +5 Greatsword and has very few other items, what's the problem. He is a very offensive combatant type who can only last a few rounds. Err, so?
As a DM, I do not impose an artificial rule that a PC cannot have an item worth more than xyz, instead, I just place items based on current challenges. Sometimes, that means a very expensive item if the challenge is very great and it makes sense for the NPC to have the item. If they overcome the challenge, the players then decide whether they want one PC to have that item, or whether they want to sell it so that all of the PCs can benefit from it.
Course, we start campaigns from level one, so I could see if a DM started the campaign out at much higher level, he would have such a house rule.