Many listeners of podcasts are doing so while multi-tasking. Text based would be requiring direct attention that I don't think would win over the vast majority of people.
Based on research, a significant majority of podcast listeners—up to 94%—multitask while tuning in, with about 59% doing so regularly. Podcasts are often chosen because they allow listeners to consume content while their hands and body are occupied with other tasks.
But even 6% to 41% of the market is still alot.
What would be the competitive advantage of your idea over a compelling web magazine or newsletter with a built in comment/chat section?
These are some of the questions I would ask and try to prove.