NBC’s sweeping shake-up of its entertainment division last week highlights the deep problems it and other networks face in continuing to produce high-quality shows as advertisers slash spending and viewers find alternate ways to watch TV. The General Electric Co.-owned network, which has seen its ratings plunge 14% this season, plans to announce this week that it will merge its two programming groups — one at the NBC network and the other at its television production studio — into one unit. For the full story click here