At least from the good reads I gather hardly people read more that 2 books per month. In a way $10 dollars is just the same thing, assuming $5 dollar is your average price of the book. If anything Amazon will profit from the all the users who read less but simply subscribe to it.
You also get the benefit of instant access to a huge catalog, though. Sometimes you just want to look up a quote in a book you read last year, or get a sample of an author that was recommended to you, or look up the context of a passage you saw quoted online, etc. That alone is not worth $10 a month, but it does add a little value beyond just reading full books.
If it also has non-fiction books - which usually are very amenable to skimming , or to reading just interesting parts , it's a very good value for $10.
I think the word "problem" is a bit of a stretch. It may not have as much actual value -- dollar cost of books read in a month/$9.99 -- as the perceived value -- unlimited. However, a successful product is about perceived value, not necessarily actual value. As the parent comment mentions, that convenience of looking something up without worrying about costs or alternate searching, and the freedom to not have to worry about the price of individual books, or having a shared kindle unlimited for a whole family with kids you want to encourage to read, are all worth something to a customer that can't be assessed in dollars. And of course, it's up to the customer to evaluate if they actually have the needs fulfilled by the product.
It's definitely a brilliant business move on Amazon's part.
Yeah, it's an interesting situation. I've been averaging around 12 books per month (audio and ebooks) pretty consistently this year, mainly because I've been really good about going to the gym (I do all my reading on an elliptical). Last year, read about 30-40 books, nearly all of it in the first few months and the last few months of the year, because during that middle period I had stopped going to the gym regularly. I probably read about 2 or 3 books during that time.
I could very much imagine someone having "clumpy" reading rates like that, where they read a lot of books in one month, then almost no books in other months.
I like to read schlocky fantasy novels and mysteries when I'm winding down in the evening, and I can plow through a book in a week easily; two or three days if I don't have a lot to do, and less than that if I have a long flight. If this offers me the ability to snag every book in a series (say, all of Richard Stark's Parker novels, or all of Robert Parker's Spenser novels), then that actually sounds like an incredible deal.
Maybe a lot of people won't get a benefit out of it, but I could easily spend more than ten bucks a month on ebooks that I don't actually care about owning for long periods of time.
What's new here? People who use their all-access passes less have always subsidized the ones who use them more, no matter the market- movies, gyms, buffetts...
It feels like gym membership for books.