They do have autothrottles. Two of them in fact. Their called "Captain" and "First Officer". At least thats how the bean counters see it. Autothrottles are an expensive option that few operators think is worth it (supposedly they save gas but someone above my pay grade did the cost/benefit analysis on that). If you're good at it, you're not adjusting power all day long. You can set an N1 or a fuel flow and pretty much leave it alone till you change something. The ERJ has a throttle "detent" where the FADECs automatically command the thrust depending on the thrust mode selected (T/O, CLB, CRZ). Trust me, its not as hard as it sounds to adjust the throttles. Just ask some Eagle or XJT guys who got to fly the ERJ with flowbacks who were used to autothrottles.