The streaming economy — and the writer’s place in it — will be a central theme of the upcoming talks between Hollywood studios and the Writers Guild of America. The union’s current contract expires on May 1,with the industry bracing for a major battle and what could be the first strike in 15 years. That has the entertainment business growing increasingly anxious that production could grind to a halt. If that weren’t enough, the entertainment companies also must reach new agreements with the major unions representing directors and actors, who might also take to the picket lines if their terms aren’t met.