Some people actually do other things while they listen to podcasts and for that having audio is useful. Not to mention few people would want to read an entire transcript of an audio podcast, which would probably run for dozens of pages. Plus you can stream the podcast without downloading it to your computer and going through all the oh so horrible steps you mention.
They don't need to control Netflix because licensing a movie to Netflix isn't giving up control. What they can't control is what Netflix pays. Obviously, Netflix isn't a company that just rolls over and gives them whatever they want. They actually have to deal on price and it's not worth it to them - except for a lot of stuff they feel isn't worth bargaining over.
Boycotting won't fix anything. They have enough business cutomers to survive even if they lose all their consumer business. And willingness to spy sure helps get those government contracts.
On top of all that, AT&T isn't the problem. It's the government and sketchy laws they use for mass surveillance. They're the ones doing the spying. AT&T is just making it easier for them. So boycott the goverment - if that's even possible.