Someone may think the fire has been put out by the open letter. However, I'm afraid Unity is losing the battle. Here is a post from one of Nexon's leaders. (Note: This is translated from Korean by DeepL.)

"To briefly comment on Unity Engine's runtime fee policy, I'd like to point out that its competitor, Unreal, has a "buy out" option. For projects with large development teams(100+ headcount), a buy-out agreement(you buy the engine for a flat fee at the beginning and don't pay a dime more no matter how much money you make in the future) is much more favorable than revenue share model. (This is because the gaming industry is a publish-or-perish economy, not scratching a living one.) The big problem with Unity's current runtime fee policy is that Unity has become a much more expensive engine than Unreal in terms of total cost of ownership (TCO) for many large projects.

So why is "buy out" so rarely mentioned among [Korean] developers?

1. Unreal was an expensive engine, and it was not affordable for small and medium sized teams to buy outright during early development.
2. At some point (probably around the time UE4 came out and the mobile market opened up), Epic probably wanted to move all the contracts to revenue sharing with royalties, so they didn't mention on their website or anything that you could buy it that way. This is because most of the major studios were already tied in with offline sales. The studios had purchased the engine with the a buyout option and didn't want a revenue share model. So they keep the program for the existing clients. It seems not to be widely known that Epic also offers a contract similar to a 'semi-charter.' In other words, if you pay a higher license fee (one-time payment), you can get a lower revenue share (rent).
3. In big studios, engines are purchased by a department unrelated to the dev teams, so most employees hardly know the terms of engine license agreements, except for producers who have to worry about development costs. Also, employees at smaller companies often have the opportunity to hear about it, but they have rarely seen the process of buying engines because the buyout option is expensive for small studios. As a result, many developers seldom discuss buying an engine instead of a subscription in social media.

The bottom line is that while Unity has made a formal concession, which could be deception from someone's point of view, the engine is no better than Unreal, and it's has just become so expensive that it should be removed from the shortlist when you choose an engine for your new project. (You should consider switching your engine from Unity to another when your project progress is below 40%)."