I understand what you are saying, but open source code cannot be a product, so it doesn't matter whether you open source everything or not. You will also feel over protective about it, not actually open sourcing everything under the most permissive license. No matter how I think about it, I can't imagine how a startup can over open source things.
That's not true. You can sell a software product and provide the source code as part of the product and/or sell the source code at a premium price to those that need/want it in order to make modifications/customizations or just to have for security/auditing purposes. However, the general stipulation is that you cannot just share that source code with everyone else, only to other customers that have also purchased, or have access to, the source code.
