Industrial demand at constant high, while residential/commercial demand next to nothing.

I have a city of approximately 50K people, with plenty of offices and industrial zones. The problem is that the demand for the office/industrial space IS CONSTANTLY HIGH, and the amount of land I've alloted for office + industrial exceeds the zones for commercial and residential combined.

I do have the Collider, so many all my residents are too smart or something to work in commercial zones? How do I get more demand for commercial and residential? Everything else is doing well (good fire protection, health, low traffic, etc.) I'll build some industry/offices for the unemployed. They'll want a little bit of housing again, and when I build housing the industrial demand shoots up like a mofo.

Thanks for any suggestions!