I'm no expert, but in simply eyeballing the bar chart, it seems it's not Q1 2019 that was the outlier. The outlier was Q1 of 2018, when extraordinary growth occurred. Now, we are back in line with the growth curve that existed before then.
Instead of only allowing family friendly content, why not innovate with parental controls? Make parental controls extremely easy to use, and effective. Perhaps integrate a fingerprint id into the remote? This wouldn't have to interfere with Apple's idea of being a destination for family content.