NORMAL, Illinois — As problems go, Rivian CEO and founder R.J. Scaringe believes he has a good one. The startup EV manufacturer has renovated a shuttered Normal factory, created thousands of jobs, raised billions of dollars and launched production of an electric pickup truck and SUV that have captured the imagination of the automotive world. But six months after the first R1T truck rolled off the assembly line at the former Mitsubishi plant, Rivian can’t build its $70,000 EVs fast enough to satisfy customer demand — or some Wall Street analysts and industry critics. Scaringe cited the simultan…