This is the wrong incentivization model because it means physicians will do everything to treat the symptoms and not even bother diagnosing the causes.
We already have a pain killer epidemic, and that would make it worse.
You can't cure what you don't know exists, but you can cure that admitting abdominal pain with painkillers and still get paid (with that model).
The point is that diagnostics are expensive, and if you're not going to be reimbursed to run them, you're going to take the risk to find the cause. What's left is curing the symptoms.
Insurance companies are incentivized to not pay anything.
They currently demand that patients do not even go to a hospital, hence the price penalties for going to an ER and lack of preventative care coverage. The only thing an insurance company will demand is what they currently do - the lowest cost, which is an Rx for pain pills.
Painkillers treat symptoms but they don't cure anything.