Netflix's 'The Witcher' is still the biggest series in the world even as it loses steam in the US, and it shows how crucial sci-fi and fantasy are for streaming TV

· Netflix's hit fantasy series, "The Witcher," is slipping in audience demand in the US but is still the most in-demand TV series across all platforms globally, according to data firm Parrot Analytics.
· "The Witcher" has held the top spot worldwide for nearly two months.
· The show's worldwide popularity is good for Netflix...