The ROI values for Undeveloped Lands are just too lousy for passive income investments.
I posted this example at the Discussion board so I'll just quote it here.
You know, i tried using Container Yards as another investment arm and I think it won't work until your passive income is much much higher, regardless of it's ROI value at the 300 villa mark. It now becomes a matter of opportunity cost. Let me explain..Enjoy!
When you buy the 11-20th container yard, the next ROI becomes 0.0667%.
The comparable ROI for about 450 villas.
Remember, you are at 300 Villas. The gap is 300-to-450 villas. Or 65-to-105 casinos. In other words, it's a pretty long journey for the rest of the Developed Lands to reach this same ROI.
Meanwhile, your container yards become locked. If you use it for a landbank again, you lose 30m off the sale just to claim back 150m (90m + 60m) for other investments. I'm not too sure how you want to calculate the opportunity cost angle, but I can offer two views.
First is if you sold off the container yards, that you added 30m to the price of the next investment.
Second is that if you didn't sell off the container yards, you added 3 time cycles to the duration of every income accumulation (assuming your current passive income of 50m). Yes, these extra time cycles will become smaller as your passive increases, to the point where you decide it is negligible (maybe around the 450 villa mark). Which is back to my beginning point that it is not yet viable to use container yards as an investment vehicle despite its current ROI.