Bullgrit also misses that, in the other published modules, it is not expected that the PCs can recover all of the treasure. (It is actually stated in module B1 that the PCs will not get all the treasure in a good dungeon.) In ToH, though, the majority of the treasure is found in one area; if the PCs succeed, they should get it all.
Also, G1-3 are part of an adventure path. In order to ensure that the characters will be ready for the challenges of the next episode, you have to cram enough XP and magical items into each module for what might have been extended adventures otherwise. There is absolutely no evidence that the books - the DMG, the MM, etc. - ever encouraged DMs to distribute loot on such a massive scale outside of competive tournament modules, adventure paths and the like.
Additionally, Giants and Dragons are some of the wealthiest foes you might face, so anything that features them will result in comparitively massive amounts of treasure but its hardly to be assumed that they are normally the sum total of all encounters you will have.
Actual treasure distribution in 1st edition following the rules per monster you face looks something like this:
Aerial Servant: -
Ankheg: 371 cp, 300 sp, 71 ep, 25% chance of 1 gem, 11% chance of 1 piece of jewelry, 6% chance of one magic item.
Giant Ant: 3% chance of one gem, 1.6% chance of one potion
Ape, Gorilla: -
Ape, Carniverous: 260 cp, 210 sp, 50 ep, 18% chance of 1 gem, 8% chance of 1 piece of jewelry, 4% chance of 1 magic item
Axebeak: -
Baboon: -
Badger: -
Barracuda: -
Baluchitherium: -
Basilisk: 420 sp, 390 ep, 880 gp, ~2 gems, 22% chance of 1 piece of jewelry, 60% chance of 1 magic item (no weapons)
Bear: -
Beaver, Giant: -
Beetle, Giant: -
Beholder: 315 pp, ~ 6 gems, ~3 pieces of jewelry, 15% of 1 magic item, 2 potions, ~1 scroll
Black Pudding: -
Blink Dog: 130 cp, 105 sp, 25 ep, 9% chance of 1 gem, 4% of 1 piece of jewelry, 2% chance of 1 magic item
Boar: -
Brain Mole: -
Brownie: 63 cp, 135 sp, 38 ep, 13% chance of 1 gem
Buffalo: -
Bugbear: 120 cp, 52 sp, 37 ep, 29 gp, 6% chance of 1 gem, 2.4% chance of 1 jewelry, 0.5% chance of 1 magic armor or weapon
Bullette: -
Bull: -
Camel: -
Carrion Crawler: 643 cp, 250 sp, 179 ep, 107 gp, 39% chance of 1 gem, 14% chance of 1 jewelry, 2.8% chance of 1 magic item (no weapons)
Catapolus: 519 cp, 294 sp, 99 ep, 35% chance of 1 gem, 20% chance of 1 jewelry, 8% chance of 1 magic item
Cattle, Wild: -
Centaur: 32 cp, 70 sp, 48 ep, 130 gp, 23 pp, ~2 gems, 29% chance of 1 jewelry, 9% chance of 1 scroll, 1% chance of 1 potion, 3% chance of 1 magic item
Centipede, Giant: -
Cerebral Parasite: -
Chimera: 420 sp, 390 ep, 880 gp, ~2 gems, 22% chance of 1 piece of jewelry, 60% chance of 1 magic item (no weapons)
Crayfish, giant: -
Crocodile: -
Demogorgon: 2000 gp, 1750 pp, 10 gems, 3 jewelry, 2 potions, ~1 scroll, ~2 magic items (not potions or scrolls)
Jubilex: 2100 sp, 750 ep, 4000 gp, 3500 pp, 20 gems, 5 jewelry
Manes: -
Orcus: 1050 sp, 375 ep, 2 potions, 40 gems, 14 pieces of jewelry, 2 potions, ~1 scroll, 70% chance of 1 magic item (not potions or scrolls)
Succubus: 315 pp, 7 gems, ~3 pieces of jewelry, 15% chance of 1 magic item
Dinosaur: -
Djinn: -
Dog: -
Dolphin: -
Doppleganger: 37 cp, 217 sp, 117 ep, 150 gp, 13% of one gem, 6% chance of one jewelry, 10% chance of 1 magic item, 3.3% chance of 1 scroll
Dragonne: 2250 cp, 875 sp, 625 ep, 500 gp, ~1 gem, 50% chance of 1 jewelry, 10% chance of 1 magic weapon, 2 potions, ~1 scroll
Dragon Turtle: 2250 cp, 875 sp, 625 ep, 2500 gp, 1750 pp, ~11 gems, ~4 jewelry, ~2 magic items (not potions or scrolls), 2 potions, ~1 scroll
Dryad: 500 gp, ~7 gems
Dwarf: 91 gp, 10 pp, 17% chance of a gem, 2% chance of 1 jewelry, 2.5% chance of 1 magic item, 3.2% chance of 1 magic weapon or armor, 0.2% chance of 1 scroll
Ear Seeker: -
Eel: -
Elemental: -
Elephant: -
Ettin: 1145 cp, 820 sp, 100 ep, 1960 gp, 35% chance of 1 gem, 16% chance of 1 jewelry, 8% chance of 1 magic item
Eye, Floating: -
Flightless Bird: -
Frog: -
Fungi, Violet: -
Gar, Giant: -
Gargoyle: 144 cp, 117 sp, 28 ep, 25 gp, 10% chance of 1 gem, 4% chance of 1jewelry, 2.2% chance of 1 magic item
Gas Spore: -
Gelatinous Cube: 14 cp, 11 sp, 7 ep, 5 gp, 4 pp, ~1 gem
Ghast: 643 cp, 250 sp, 179 ep, 678 gp, 500 pp, ~4 gems, ~1 jewelry, 2.8% chance of 1 magic item (no weapons), 57% chance of 1 potion, 36% chance of 1 scroll
Ghost: 275 cp, 1625 sp, 875 ep, 1125 gp, 98% chance of 1 gem, 45% chance of 1 jewelry, 2 potions, 75% chance of 1 magic item, 25% chance of 1 scroll
Ghoul: 173 cp, 67 sp, 48 ep, 38 gp, 10% chance of 1 gem, 4% chance of 1 jewelry, 0.7% chance of 1 magic weapon, 9.6% chance of 1 scroll
Giant, Cloud: 78 cp, 464 sp, 250 ep, 3821 gp, 143 pp, ~1 gem, 7.5% chance of 1 jewelry, 21% chance of 1 magic item, 7% chance of 1 scroll
And of course, according to the discussion in the DMG, most of that coin should be converted to tradable commodities, valuable goods, and the like rather than in an easily portable form.