it is inclusive. Should have gear and coin at least to that level.
Wealth is all-inclusive, everything counts. But you don't have to do anything. You could drop loot that the PCs might like, handwave everything and just let them shop appropriately when in town or keep track of the value of every piece of equipment the PCs scrounge from the dragon's lair. You can play the game with PCs above the wealth guidelines, below it or right on the mark. Whatever tickles your fancy, really.
But when the party roughly has what it's "supposed" to have, it becomes easier to gauge their combat abilities and Challenge Rating.
Yeah, that chart is just so you know if you have to adjust the challenge metrics up or down by a level or two. Super-rich party, raise the CRs you're using by one or two.
If you drop the treasure you want, and it turns out that you prefer a more "low magic" style with less stuff, then you'll see that their total wealth is several levels down on the chart. All this means is you will be able to challenge them with lower CR monsters.