A better analogy: imagine if someone built a public water fountain, then chess.com set up next to it selling the exact same water for $100/year while limiting the public fountain to 1 cup per day through lobbying. Then they sponsored all the popular hydration influencers to only drink their bottled water on camera.
> Cause you can just go to a bar and get it for free.
Not at the same convenience, can you ;) So they are selling convenience. Chess.com isn't selling convenience - both platforms are websites you access identically. They're not offering portability or solving a distribution problem. They're artificially limiting a digital service that costs them essentially nothing to provide unlimited access to.
How, specifically, are chess.com limiting anyone using lichess?
> that costs them essentially nothing
If you know how to run such a platform for free, then I'm sure you could sell your knowledge for a lot of money. And the company running chess.com would be your highest paying customer.
In other words, I think you are underestimating the effort. Just ask the lichess guys.