I don't want to turn this into an edition war. I'm just going to relate my experiences as a 1st edition player.
The 1st edition DMG was very clear on the idea that wealth should be difficult to acquire, usually not in the form of actual cash (so a result of 1000 gp might or should be interpreted by the DM as 100 gp plus trade goods that could be sold for 900 gp), should be subject to taxation, and should only rarely contain magical items. These guidelines were backed up strongly by the MM treasure tables. Many observers look at the monster manual treasure tables and make extravagent claims about the wealth generated by rolling on those tables. I strongly suggest that those observers have never done the actual math. Not only is the chance of wealth relatively low for all but the most generous tables, but if you actually read the rules you'll see that that the result is the assumed amount for an average lair of several individuals. If you actually divide the average wealth by the average number of individuals, I think most people will be startled by how little treasure the 1st MM treasure tables actually produce for anything less than say a large ancient red dragons, beholders, or other top end monsters.
Likewise, the DMG was very clear that while you can sell magic items in large markets, even in large markets thier will be few if any magic items for sell. It was assumed by me and by every DM I played under in 1st edition, that the only magic items which could be regularly obtained in shops were potions and scrolls and that these were available in limited quanities as determined by the DM (often randomly). Otherwise, you had to find things in adventurers or else adventure to find someone willing and able to accept a commission to produce a particular item you desired (after which it might take an in game year for the item to actually be manufactured). Often this person would accept payment only in the form of a favor, which meant doing some adventure and recovering some gizmo that they'd trade for the item you wanted.
These are the guidelines that I used, and these are the guidelines used by DMs I played with.
Now, it is certainly true that published modules contained more treasure than was suggested by the DMG or by the MM. Most DMs I played with accepted this on two accounts. First, the DMG and the MM both agreed that the best treasure was to be found in dungeons and the guidelines should be relaxed in dungeons. And secondly, it was assumed that not all the treasure would be obtained (it usually wasn't), that the enormous treasure was a product of the modules need to produce fast leveling within the limited space provided by the text, and that a DM would pare back the suggested treasure/and or elaborate on the published module as suited the needs of his campaign. Typically, I would find myself removing certain stashes of magical treasure from published module, reducing hordes of coin, usually 2-3 magic items which I considered to be too easily obtained for the power of the magic involved (a mace +3 randomly in an otherwise empty room).
Many DMs I knew in 1st edition fiddled with the XP tables and such to try to reduce the need to dole out gold in order to level, which was the driving force behind large amounts of coin in published modules.
My most influential guidelines to how much treasure a dungeon should have were actually the random dungeon generating tables in the back of the 1st edition DMG. I typically would place important items designed to appeal to particular characters, and randomly roll up treasure elsewhere.
As a player, I don't recall ever being upset that I had all sorts of random magic items. In 1st edition, at least amongst the people I played with, for the most part thier was little emphasis on optimizing your character. I have a hard time understanding the perspective of the modern player, except that it seems to be very much informed by games like Diablo. Random magic items meant you had tools stashed away for when you need them. A folding boat was great. Who knew when you might need a boat? No one was worried that you might never need a boat. It was more like, "If we need a boat, we're set." No one would sell a magic item that had any sort of potential use at all. Wand charges were horded for emergencies. Who knew when you might find another one? Expect to need that wand to last for many many sessions. Don't waste it.
I know of a campaign that actually ended up hinging in its climatic moment on the fact that someone had not sold a wand of fire extinguishing. I honestly can't imagine a default 3E campaign ever being in a situation like that.
