Sharding in Open-Source version isn't automatic, so you have to manage it yourself, as in there is no automatic resharding and you need to insert data accordingly. IMO that's the biggest bottleneck in its adoption at larger scale. Previously you didn't have a choice in terms of whether or not to do sharding (and compute/storage separation if you want it), now you have more options, including one from ClickHouse authors themselves.
Apparently it's not a bottleneck, it's a sales funnel.
I don't see a contradiction here tbh. There's nothing wrong in not providing some extra functionality for free (especially for features that users will pay for). If you have engineering resources to manage sharding manually you're welcome to do so. Since ClickHouse is a commercial company and not part of Yandex they need to earn money one way or another to fund the database development.