"Amazon S3 automatically scales to high request rates. For example, your application can achieve at least 3,500 PUT/COPY/POST/DELETE or 5,500 GET/HEAD requests per second per prefix in a bucket. There are no limits to the number of prefixes in a bucket. You can increase your read or write performance by parallelizing reads. For example, if you create 10 prefixes in an Amazon S3 bucket to parallelize reads, you could scale your read performance to 55,000 read requests per second."

With 500 prefixes it doesn't matter if you're Netflix or a student working on a distributed computing project, you can get that 1.6m requests.

There is no limit to the number of prefixes in a bucket. You can scale to be arbitrarily large.