Because there is a natural monopoly in being a trusted provider of legal transaction services. Both for integrations and for the fact that no one wants to risk

Because there is a natural monopoly in being a trusted provider of legal transaction services. Both for integrations and for the fact that no one wants to risk their job saving a few dollars on digital signatures. And no one wants to explain to a future acquirer / legal inquiry / judge / whatever that they are using some weird alternative. “We process the contracts with Docusign” is a safe thing to say. If that wasn’t good enough, a whole lot of other people would also be in trouble, so the collective hallucination that is our legal system will support it.