I want it. Why is it missing in the DMG? Doesn't need to be hard and fast. I would just like a guideline.
Why is it necessary? There's only so many things that people can spend their money on, and since they got rid of buying magic items you don't have to worry about people getting gold just to power themselves up through magic. Doesn't seem needed to me.
What's the Problem with the Table on DMG Page 38?
There is this small paragraph in the DMG on page 133.
"You can hand out as much or as little treasure as you want. Over the course of a typical campaign, a party finds treasure hoards amounting to seven rolls on the Challenge 0- 4 table, eighteen rolls on the Challenge 5- 10 table, twelve rolls on the Challenge 11- 16 table, and eight rolls on the Challenge 17+ table."
The tables referenced are the Treasure Hoard Tables. Earlier in the section it also mentions that each roll doesn't have to be a separate haul. If a monster is known as a treasure collector like dragons, it's hoard can contain multiple rolls on the appropriate table.
I assumed that this was correlated with the number of encounters you would expect to have over those levels, but have not actually backed out the math.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.