Rates are absolutely negotiable.
And prospective users can look at the published prices, and see that historically they've gone down more than they've gone up (although obviously that trend could reverse).
So people think they're safe from the risk of Amazon quadrupling their bill over night.
Of course, vendor lock-in can have other negative effects, but apparently people aren't worried about them, or at least think AWS is no worse than the alternatives.
[1]: https://news.ycombinator.com/item?id=12392081
[2]: https://minio.io/
[1]: https://hasura.io
It's such a poor argument. I was a developer long before AWS appeared and I've used so many open sources packages that were profoundly reliable. In many cases it just takes a daemon restart. And while it's not exciting to set up some of that stuff, it's far more tolerable than writing a CloudFormation template.