https://screenrant.com/why-british-tv-show-seasons-shorter-than-american/

It is common knowledge that most British TV shows tend to be much shorter than American ones, but what is the reason for this difference?

Historically, British television developed earlier than American television and had different programming formats. Early British TV was influenced by the BBC's mission to educate, inform, and entertain the public with a variety of content, including shorter dramas, comedies, and news programs. It's important to note that while there are general trends, there are exceptions in both British and American TV. Factors such as genre, target audience, creative decisions, and industry trends also play a role in determining episode length. As the global television landscape continues to evolve, we may see further shifts in episode lengths and formats.