That's the thing: it's not possible to answer this question, since the cut Unity gets is not tied to the revenue of the developer anymore. You pay per user install. In the absolute worst case of people trying to abuse this structure, it would be possible for the developer to owe more than their revenue!

That only applies to F2P games essentially thought, right?

Initially, this applied to every single update, every single reinstall, and anything that changed your IP. Every load of a unity web game.

All of those counted as a new install, and this was stated to be intentional by unity to all the journalists who reached out and by their internal developers on the support forum.

So the long tail of things like your customers buying a new phone == old apps get transferred == that counts as a new install and you get charged. Reinstall a game from steam or change the install drive or directory? Same thing.

Beyond devs and game types that are affected by legitimate usage, there is the clear problem of malicious installs (what a phrase) and abuse. Unity's answer to that was that proprietary secret internal models would solve abuse, but also that developers would have to reach out with proof of being falsely billed after it happened. And just kinda hope that unity would have the support and billing staff to ever actually deal with that problem.

No, it applies to all games. Say you publish an iOS game for 1$, and a user installs it on two devices which he replaces after a couple of years - you'll owe Unity more money than you took in from the sale.

If it's 50k for 500k revenue then you think it's reasonable for Unity to charge twice the price of Unreal engine's royalties, plus additional liabilities for any future installs of the game that customers previously purchased and will no longer be paying for.