I use to play sim city 2000 as much as I do Minecraft. I never did find out what "Industry needs connection" means.
It meant you needed more infrastructure to connect your city and its industries with neighbouring cities. Things like seaports and highways. I don't think any iteration of SimCity has been as good as 2000.
No, you just needed highways, or even railroads, heading out to the edge of the map, to the other cities. As long as those are connected somehow to your inner-city infrastructure.
"Industry needs connection" It was very frustrating. I have not played any version since then. But it was fun. Now that I think about it, it has alot of similarities to Minecraft.
http://www.planetminecraft.com/project/doshtopolis-by-moneybob/ The image was rendered using a program called Chunky.