Because creating good documentation suitable for external consumers costs money, and even if you have decent documentation, people buying small quantities of parts can end up costing companies money just to interact with one of their application engineers. If you're not set up for it (very few companies are), it literally is negative value to answer support questions for small time customers.
I'm not sure how your answer relates to the question about why they won't release documentation they already have. Are you saying that releasing documentation is going to increase the number of support questions?
If you want to sell or limit support, why not do that without the documentation complications?
> Are you saying that releasing documentation is going to increase the number of support questions?
Yes, absolutely. Notoriously, smaller customers are more needy in fact. The bigger the customer, the more competent their engineers tend to be (or, the more time they have to spend figuring out how to use your stuff). Smaller customers try to offload support onto vendors, which pushes burden onto internal vendor teams (who don't want to provide the support...).
Smaller customers are more needy, sure, but there's a couple steps missing here. Is better public documentation going to bring in a lot more small customers, more than it solves problems? Is an NDA by itself keeping away lots of small customers?
> Is better public documentation going to bring in a lot more small customers, more than it solves problems?
Maybe. The other thing is that public documentation gets a lot more scrutiny than internal documentation. You don't have any resource to talk to, so something like typos or mistakes need to be corrected rather than just papered over by a helpful applications engineer.
