It might be more precise to say that "licenses do not govern all behavior in open source." But the flip side of that acknowledgment should be to notice that while obedience to licenses is governed by force of law, all other behavior common open source is essentially ungoverned, or governed in an arbitrary, self-appointed fashion.

There's this tendency in permissive open source to reify "social norms" into their own sort of law, and then indict people based on the violations of them (as they are defined by the speaker.) Social norms are a survey of behavior, not an enforcer of behavior. I may not feel good going against the wishes of the author of a piece of software that is under a permissive license. If enough people feel like me, honoring that sort of request from an author may become a "social norm," especially if people who agree with me start to punish people who don't agree with me, and that creates a pressure for people who don't agree or are neutral to conform to avoid being shunned. This is where actual government is introduced, in the people who refuse to hire, work with, or do business with other people.

That's fine, but if you're going to use your authority and autonomy to enforce your arbitrary moral rules, you shouldn't be surprised when massive and massively powerful corporations use their authority and autonomy in the way they see fit. You don't shun Amazon, Amazon shuns you.

That's why there's an advantage in encoding whatever moral stance you want to take into your license, and in confederating with others who share your beliefs (as explicitly stated in the license) in order to form a more powerful unit. Then the courts can defend you against Amazon, and a side effect will be that there will be even more power as a community to promulgate your extra-license norms.

Also, well-governed GPL within a community isn't incompatible with secret sauce. Dual-licensing schemes give the power to create good businesses, through exchange of permissive relicenses, subsidy and mergers. We just have to be creative about it.

If a walled-garden, curated experience can be an advantage in the market, there's no reason you can't create one with GPL'd software, cross-licensed permissively, where the authors, developers, marketers and salespeople get paid. Just uphold the philosophy that you're not going to restrict people's access to and ability to modify their own devices, or use incompatibility to create a moat between yourself and competitors. If possible, encode it in the permissive license. That doesn't mean that you have to recommend that people modify their own devices, or that you have to distribute code, or even make it at all easy to do. If people do modify their own devices or software, it doesn't mean that you can't void their warranty or cut them off from your cloud services. If you notice a player out there doing a good job of modifying your devices or software, bring them inside to do it, giving your users less reason to stray.

Apple and Google built their businesses on a mix of permissive open source, proprietary bits, and exclusive services. The same can be done with a mix of GPL, relicensed GPL to permissive licenses with proprietary bits included, and exclusive services. The difference is that the GPL software commons will be built up during the process, and the use of that GPL software will be an advantage the small confederating players will have over the massive multinationals.