$29/mo seems high for the vast majority of podcasts, which are labors of love run on shoestring budgets. Of course, it's peanuts for the high traffic sites. Did you consider a Dropbox-like pricing model, e.g., free for low-traffic sites?
Especially if podcasters will bring their audience a free tier can boost growth. Then charge for power tools. Find the things that professional podcasters need that amateur podcasters don't and charge for those.