Some object stores do this, but aws S3 for example does not. You can list the contents of buckets, nicely sorted by name. You can mimic directory structures if you want.
However, you touched a key point: object stores are all about throughput, not latency. You can store at a GB/s (if you have the pipes), but even checking if an object exists will cost you a few milliseconds.
However, you touched a key point: object stores are all about throughput, not latency. You can store at a GB/s (if you have the pipes), but even checking if an object exists will cost you a few milliseconds.