Correct. This is what makes me feel guilty about releasing a closed-source product, or even one with a non-OSI license. It’s irrational, but I feel like I’ve benefited so massively from FOSS that I owe it to the community to contribute back.
EDIT: as another commenter wrote below, OSI is driven by massive cloud vendors, who have a vested interest in having their freedoms to take projects and monetize them. Perhaps a somewhat restrictive license isn’t a bad thing.
Open source as a byproduct of a company absolutely works - it's been proven by tons of tech companies.
But if you open source your revenue-generating parts, and only charge for support/managed version/enterprisey features you'll end up with quite weird incentives, particularly with infrastructure tools, in which the big cloud providers will happily compete with you, using the version you open sourced and providing and ecosystem to their customers that one simply cannot compete with
In the sense that most modern programming languages and compilers are open-source, sure, nothing outside the embedded world can truly be built without relying on open source.
There are still native shops that rely on very little open source, though at this point probably only in niches like gamedev or defence.
This is not true even in those spaces anymore. Games these days require libraries like SDL, or (increasingly) use engines like Godot.
Defense is a weird place, but open source is used quite a lot there, it's often required to do so and to record the open source consumed to produce a product. And often times, it must be commercial open source where you can get engineering support for the lifetime of the product's existence.
