This is a thing actually on Breaker and Stitcher. The show I host offers this as a "premium feed."

Not a ton of interest, unsurprisingly, as most people don't experience enough inconvenience in an ad to shell out.

Some do this. The Savage Lovecast, for instance, has a subscriber-only feed that delivers the podcast with no ads and more content.

Are the ads really so bad? they're skippable quite easily if you are really annoyed.

Not so easy to skip if you're doing something with your hands - cooking, riding a bicycle, etc.