The struggle is not an issue across the league. As Kerry Crowley of the San Jose Mercury News pointed out, the San Francisco Giants had scored just 83 runs in a span of 21 games. That is an average just below 4 runs.
For years, the Giants offense was built to score just enough runs. Just enough runs was usually 4 runs per game as their chances of winning greatly increased at that point.
If the Giants struggle to score runs in the Cactus League, the issue will not improve as they move back to the cold, expansive dimensions of Oracle Park.