You are correct, MIT is very permissive, but as long as you don't have a product, it doesn't matter. This is largely because "distribution" is not enforced with any open source licence I know. For example I customise Joomla sites for clients. I distribute to my client. My client chooses to not distribute to anyone.
On top of that many GPL libraries (again for Joomla) charge on a per site basis. You may argue they can't, but it doesn't mean that people won't simply pay it. In the end they can only refuse support for each unlicenced site, but that may be enough to get a high percentage of users paying for it (if its cheap enough)