That's a more difficult case of course. But I believe enterprise support and custom enterprise features/addons could help in the case of languages.
> corporation controlling at least the proprietary components?
WP plugins are still GPL. But the users can buy, download them from the original source, install them on their site, and update them from their site with one click. Coupled with premium support, this works well. Its a bigger risk and hassle to 'pirate' the plugins from 3rd parties rather than just getting everything directly from the source. (though such 'piracy' does have impact).
In any case, one organization controlling at least the proprietary, custom enterprise components is much better than the alternative.
Look at tailwinds, open source lib with saas opportunities that netted the creator millions of dollars
Freemium format. It floats the WordPress plugin ecosystem. That ecosystem has $1 bn size. Likely larger now since that statistic was made 1-2 years ago.
You give the base software and most if it free. You provide paid addons for niche, corporate, business use cases etc. Everyone is happy - the userbase gets their software free, advanced & business users have advanced features that could not have made it into the main software in addition to having paid support. And most important for everyone - the project & its organization can sustain itself and it can keep maintaining its software.