Someday, all of medicine will be testable. The cause of all diseases will be known, and you will be able to take a test to tell you if you have a problem. Whether the cause is a gene, a thousand genes, a hormone imbalance, a chemical imbalance, environmental, or whatever. Eventually, we will have the human body all figured out.
Computing power continues to grow. In time, it will reach the level where everyone has regular common access to what today is a supercomputer.
When those days arrive, human doctors will no longer be needed or even desirable. Why risk someone who may unconsciously have it out for you when you can walk up to a computer, have it scan you, maybe test your breath, blood, or spit and tell you exactly what is wrong with you. Then you get the treatment and be on your way.
I’m in my mid-40’s and I don’t think it will happen in my lifetime. It would take the right people wanting to make it happen and pouring the right amounts of money into it. Right now those with that type of money seem more invested in going to outer space or hacking aging.