Some of these books are over 40hrs long I listen to. My current book, Oathbringer, is 55hrs. I find the length and professional voice acting to provide more than enough value for the $15/month audible charges (hope I don't sound like a shill).
Certainly better than 2 movies a month, imo :)
edit: I do wish you got a free kindle version with audible purchase...
They can be very expensive if you get them one at a time without buying them on sale, but it was like that long before Amazon.
I've been listening to audio books for almost 2 decades. Back before Audible or Amazon or anyone else, audio books came on dozen-packs of cassette tapes and then CDs, and you'd get them at book stores or the library. If you chose to buy them, they'd cost in the neighborhood of $50 per book for your average book. Then Audible came around and started offering a plan giving two books every month for like $15/month. Then Audible partnered with Apple and got a real promotional bump from affiliation with iTunes and soon Audible as a brand became almost synonymous with audio books. The price for that 2 book plan went up a small amount over the years, but not by much, and they grandfathered previous customers. Then Amazon bought Audible and the price didn't change. Actually, almost nothing changed at all, except that they started getting a bunch of new free content, daily deals, frequent sales, and unlimited free returns. I think the only thing they lost in the acquisition was referral bonuses.
But going back to the context of my original point, if you go hunting for a particular book on Audible today, you're likely to find that it costs $20, $30, or even $40. And you're right, it's pretty hard for most people to even consider paying that much. But I think that that's not how most customers actually get their audiobooks today. It's kinda like...have you ever gone into one of those stores where everything is always on sale? Which price is the real price?