I would tend to agree that there's not enough time in 3p if both other players go for Marauder/IGG.
The 3 piles (Ruins, Curses and IGGs) will be gone so very fast.
There are also too many expensive cards, which makes it harder to get a huge hand and play some Goons megaturn. Having only City/Embassy for draw is not that enticing. Yeah, you could throw in some Cartographers and Apothecaries and Warehouses, but I don't think you have time for any of that as you have no pile control whatsover.
You should be happy if you can get a Duchy. Maybe you can skip IGG yourself?