What if people are already using your product despite poor documentation?

Then what's your motivation to make the documentation better, and the abstractions easy to understand?

At worst, you could simply believing that you work in an inherently complicated field where people must pay for services and training just to get by.

nobody can stop you from doing a bad service company, but no one can stop you from doing a bad product company as well IMHO. The difference from an open source point of view is that the community can write better documentation, but can hardly fight you if the open source main developers are trying to push forward a business model where part of the code is closed, or there are commercial plugins that are very useful, and so forth.