Why Can't We Buy Support and Jungle Items Together?

With the way support items are now, what is the harm in allowing a champion, like Ivern, to run a support item and a jungle item?

Maybe make a third jungle item, that doubles as a support item, like Tracking Knife, but it still needs to be upgraded like the other support items. https://vignette.wikia.nocookie.net/leagueoflegends/images/9/9e/Tracker%27s_Knife_item.png

What with it no longer giving 3 wards right off the bat, it would limit it's impact in the early and mid game in high level play.

It could have a smite that rewards gold to allies when smiting a minion, maybe double the charges, cut it's cooldown, damage, and heals in half to make it easier to finish the quest with.

"It's the tax that gets ya." - Roamin the Paladin