Elastic.co has a lot of proprietary add-ons in their cloud and subscription tiers, for example machine learning, application tracing, endpoint security, threat detection, in addition to enhancements to the core software, like fine-grained access control. This is where much of their development and marketing effort goes, and is what differentiates them from others offering ES-as-a-service.

Unfortunately for them a lot of users don't need any of that, and are just fine with the formerly-OSS core.