General Discussion4k offlane discusion

Hi all. I've be playing offlane lately very often and it gave results. I saw post here on dotabuff, someone said that playing offlane in this shit brackets 3k 4k is actually best way to climb, and i can agree, in most of cases it is.
My opinion is that u can carry your game (expecially with broken heroes for low brackets like underlord) if your cores fail, or even support if u have classic 4k supports who dont buy shit.

Now my question is, is it good and how much is it worth buying support items in that case? I mean is it worth buying that stuff and is that 500 - 750 gold is 2 much for position 3 to spend in mid game period or it can be actually game winning worth?
Opinions on pos 3 generally in both sides, helping your cores carry and supports support the game?