[arbie]

There are many industries where the workflow espoused in the manual IS the secret sauce, and, once replicated, can be replaced by a much cheaper product.

In these cases, you will never recoup your NRE.

[nitwit005]

Except, it's easy for competitors to get a copy if they care to. They can ask around for a copy, or just buy your product and get a login.

Oracle has sued competitors for handing out copies of the manual, suggesting requiring a login isn't much of a barrier: https://www.bizjournals.com/sanjose/news/2013/06/18/oracle-w...