So if they have been lowering prices for 30 years, why do the prices keep going up?

I know there are increased costs due to medical advances, but this only accounts for half the increase in costs according to studies, so the rise from 5% of GDP in the 60's to 16% of GDP today, especially seeing the massive increase in GDP during that period, does not chime at all with the idea that the insurance industry is lowering prices in any meaningful way.

In fact, any rational observer might well assume exactly the opposite.