Simply put, it's a UI issue that affects every aspect of the business. Podcasts have an artificially diminished shelf-life. If you don't release an episode every two weeks, your show gets buried in the library. It means the format is synonymous with churned, radio broadcast-like content.

This has also affected the monetization model. Most ads use promo codes for services, but those promos expire and change, rendering that content valueless. Given these limitations, it's a miracle any producers are funding serialized content that actually has a conclusion.