Macworld In a perfect walled garden, every digital good and service would be on a level playing field and creators would all have an equal shot at succeeding. In the real world, that’s just not the case. According to a report by Semafor, a podcaster looking to get featured in one of the main slots in the Podcast app’s Browse tab should start by joining Apple Podcasts Subscriptions, which offers listeners “premium benefits like ad-free listening, early access, and bonus episodes” for a monthly fee. Podcasters need to join Apple Podcasters Program for $20 a year. And of course, Apple takes its s…