Insurance Companies as Investment Vehicles

I have this belief that some of the current healthcare crisis can be tied to the fact that insurance companies are now publicly traded entities that are therefore expected to show geometric growth over time. I wonder if it would be possible to produce a model that basically shows that the only way in which this can happen over any substantial window of time is by successively (geometrically?) reducing costs over time - which I believe must eventually come down to cutting services (i.e., covering fewer and fewer procedures and people). I think that the parameters that might go into this are something like diagnosis rates (is this the same as disease frequency?), capital expenditures, etc. In fact, it might be a very simple logistic sort of model that would give a carrying capacity kind of argument...