they don't need another problem DI system but both port + DI some are already using!!
As much as I agree, it will never happen. Port + DI is too complex, and costs too much money. I almost wonder why they don't go back to an enrichment-style system, like the early Toyota's and others. A single injector, mounted just behind the throttle body, that sprayed fuel when the engine was cold. In theory, couldn't this single injector be used to momentarily spray an evenly-distributed mist of fuel across the intake valves? That would coat the valves with fuel and break down any deposits that may build up. It wouldn't have to run constantly, just once every few hundred miles under high-load situations where intake velocity is high to aid in deposit removal.