Ind-M development issue

[Flobey 0]

 So, I've been creating a new region and starting with my primary strategy. I develop several medium tiles with nothing but dirty industry and $R. I provide only the bare minimum services and I let it grow until development levels off at about 150K residential population. This is about how much population can be held on approximately 50% of a medium tile zoned medium density. I keep the population poor and dumb for a significant amount of time just to build capital. Once I am at this stage, usually the city tile is like this:

land area is all zoned, 45% med. density residential 45% med.density industrial with dirty development and 10% commercial service (no office) in a strip up the middle, separating industry from residential.

It's also important to note that in addition to NAM I am using the industry job quadrupler mod, so with my jobs and population in equilibrium, there are still lots of free industrial tiles.

My issue arises after I am at this stage. I finally decide to plop in enough large elementary schools and hospitals to serve the whole population. I run the simulation many more years with tax brackets still excluding manufacturing industry and R$$ to spike the demand as the population becomes smarter and healthier. I have been playing long enough to have all the major obstacles taken care of, my mass transit runs well, road congestion is minimized and basically everything is accounted for. When I finally level the tax bracket to bring in the manufacturing industry I end up with demand through the roof and desirability is in the green. This is good. Despite the pollution from the dirty industry, the manufacturing industry does decide to move in, right among the existing dirty. It continues to develop, yet levels off at between 15K and 20K manufacturing jobs. I want it to keep going. When I look at my diagnostics I can rule out caps. I have effective running freight rail and I know the industrial demand is not capped because I still have a huge demand bar in the graph. I check out the IND-M desirability and it is still green.

So, to reduce the problem to the simplest terms...my manufacturing development has leveled off, yet I still have demand off the charts, free space, AND desirability in bright green. What am I missing? What else could be stunting the growth?

[Tysons4 68]

don't forget about region play... start a new city and zone some industrial (keep the power away and give it some water) you should see some ht and m i move right in if demand is as high as you say

[local_authority01 3]

You might need more people. With Industry jobs quadrupled, you shouldn't have to zone industry in 45% of your city. Lack of workers is likely one of the causes of your problem.