Technically it might be possible, like with military aircraft, but not at high commercial airline safety levels unless you have fully qualified pilots monitoring from the ground at any time. If you do all the cost of the failproof datalink comes on top. So manned cockpits must be cheaper and the flying public is more fearsome than the industry. Let just one crash happen and all your remote controlled aircraft can be converted to freighters. Two pilots "at work" in the cockpit are a minimum that will stay for quite some time.