Interesting point of comparison to, say, iOS development, which costs $99/yr, full stop, not per-seat.
While I agree it's not a fair comparison, the Unity fee at least provides substantially more value than Apple's, like covering the publishing process for multiple console platforms, which is almost always relatively expensive.
Assuming you're not doing it as a hobby the flat cost is far more economical unless you release a lemon in which case the scaling cost does minimize the losses at least.
According to Apple's Powerpoint in Epic v Fortnite [1] 30% is more or less standard, for consoles as well as on PC. Microsoft was supposedly also going to 88/12 though that seems like it might have been dropped.
1. https://www.theverge.com/2021/5/3/22417725/apple-vs-epic-ful... (slide 15)